Ordinance No. 4,026"Septic Tank," means a watertight, covered receptacle designed and
constructed to receive the discharge of sewage from a building sewer,
separate solids from the liquid, digest organic matter under anaerobic
conditions and store digested solids through a period of detention, and
allow the clarified liquids to be dispose of in an acceptable manner.
"Holding . Tank," means an approved non- corrosive watertight and
airtight tank used to receive and store sewage wastes in an anaerobic
condition until its ultimate disposal to an approved treatment facility.
"Aerobic Sewage Facility," means a sewage treatment facility that
disposes of waste by biological treatment in the presence of oxygen.
"Anaerobic Sewage Facility," means a sewage treatment facility that
disposes of waste by biological treatment in the absence of oxygen.
ORDINANCE NO. 4026`"
�1IE
AN: ORDINANCE OF THE CITY COUNC;.IL OF THE CITY MF.
BAYTOWN, TEXAS, AMENDING CIiAPTER 34 "WASTE' DISPOSAL " BY:
ADOINO -,AA TIC'.IE III, "PRIVATE SEWAGE `FACHATES;':AtEPEALi0;
CONFLICTING ORDINANCES; CONTAINING A SAVINGS CLAUSE;;,_
PRESCRIBING.. A MAX INM; PENALTY OF ;'ONE ''THOUSAND AN®
NO /100 (51,000.00) DOLLARS= AND PROVIDINIG FOR= THE
P1 J8L ICATiON AND .EFFECTIVE DATE ZERt .
iY
**+►** a***** �##* Mi��* �t�+r�t+r *+� * *�r� * *�t� * * *+� * *�i r- ire►** �r *at�s�fr� *aas�os�r�settsssf��
BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF BAYTOWN,.:
TEXAS:
Section, 1: That the Code of Ordinances of the City of Baytown is ,hereby;
amended by the amendment of Chapter 34, "Waste Disposal," by adding Article III;'
"Private Sewage Facilities," which shall read as follows:
CHAPTER 34, WASTE DISPOSAL
Article 1% Private Sewage Facilities
Sec. 344M Definitions
�h
The followirig definitions shall apply to this Article:
"Sewage," means any wastewater containing animal or vegetable
matter in suspension or solution, .including liquids containing chemicals
in solution, domestic wastewater, and laundry wastes. (Used
interchangeably with the term wastewater.)
"Private Sewage Facilities," means facilities provided to serve only an
individual household, multiple unit residential 'structures or commercial .
establishment within a designated area and whose operation.., and
maintenance is the sole responsibility of the occupant or owner of the
property. Such facilities provide for the disposal of treated wastewater
by subsoil absorption, evaporation, evapotranspiration, or any other .
manner other than connection to a public sewer line and are not
subject to the issuance of wastewater discharge orders by the Texas
Department of Water Resources
The phrase "Private Sewage Facility" does not include
porta -cans, ports- johns, chemical toilets, or other portable toilets, by
whatever name known, when utilized for a period of less than three (3)
days at the site of large public or social gatherings or on a temporary
basis on construction sites during actual construction under permit.
"Septic Tank," means a watertight, covered receptacle designed and
constructed to receive the discharge of sewage from a building sewer,
separate solids from the liquid, digest organic matter under anaerobic
conditions and store digested solids through a period of detention, and
allow the clarified liquids to be dispose of in an acceptable manner.
"Holding . Tank," means an approved non- corrosive watertight and
airtight tank used to receive and store sewage wastes in an anaerobic
condition until its ultimate disposal to an approved treatment facility.
"Aerobic Sewage Facility," means a sewage treatment facility that
disposes of waste by biological treatment in the presence of oxygen.
"Anaerobic Sewage Facility," means a sewage treatment facility that
disposes of waste by biological treatment in the absence of oxygen.
1�1
E
"Percolation Test," means a test performed to determine the absorptive
capacity of .the soil and its suitability for septic tank absorption fields.
These tests= should be performed during the season when the water
table is highest and the soil is at minimum absorptive capacity.
Sec. 34-41. Adoption of construction standards for private sewage
faculties
Except as provided in this Article, the Texas Department of
Health publication entitled "Construction Standards for Private Sewage
Facilities, ". ;including amendments hereinafter referred to as
"construction standards," a copy of which Is attached hereto as Exhibit
"A" and made a part hereof for all purposes, and copies of which are
on......... file with the Health Department and Inspection Department' of the
Ci of Baytown, is hereby adopted and incorporated as fully as if set
forth . at length herein, and the provisions therein shall be controlling in
the, design and construction of private sewage facilities within the City
of Baytown.
Sec. 34-42. Approval of innovative designs
.New or innovative designs of private sewage facilities prohibited
by this Article are encouraged. The City of Baytown Chief Sanitarian
may approve uch designs which prove to be reliable and protect the
public health, welfare and environment if appropriate construction
.standards `are adopted under this Article.
Sec. 34-430 Illegal private sewage facilities.
a) A person commits an offense if he intentionally or knowingly
constructs, uses, or retains a cesspool, bore hole or injection well,
seepage° pit, or any other private sewage facility or system not
authorized by, this Article.
b) ` An offense under this section is a misdemeanor punishable by
a fine not less than $500.00 and not to exceed $1,000.00.
Sec. 34-44. Illegal construction or installation of private sewage
facilities without a building permit.
a) A person commits an offense if he intentionally or knowingly
constructs or installs a private sewage facility authorized by Sec. 34-47
without a permit issued by the City of Baytown Chief Building
Official.
b) An offense under this section is a misdemeanor punishable by
a fine not to exceed $200.00.
Sec. 34 -45. Illegal use or retention of private sewage facility without
a permit.
a) A person commits an offense if he intentionally or knowingly
uses or retains a private sewage facility without a permit issued by the
City of Baytown lrhief Sanitarian.
b) An offense under this sections is a misdemeanor punishable
by a fine not less than $200.00 and not to exceed $1,000.00.
Sec. 34-46. Illegal use or retention of private sewage facility which
discharges to the ground surface.
a) A person commits an offense if he intentionally or knowingly
uses or retains a private sewage facility which discharges to the
surface of the ground, including ditches, streams, ponds, lakes, bay, or
adjacent lots or tracts, except in a permitted holding tank.
b) An offense under this section is a misdemeanor punishable by
a fine not less than $500.00 and not to exceed $1,000.00.
Sec. 34 -47. Failure to provide trip tickets for permitted holding tank
facilities
a) A permittee or waste disposal carrier under this Article,
commits an offense if he intentionally or knowingly fails or refuses to
provide waste disposal carrier trip tickets detailing the waste disposal,
L
including name and location of the permitted facility,,gallons per, trip,
gallons to date by calendar year and the names and location .of the
ultimate.: `disposal site, for sewage disposal -.from a permitted holding
tank facility upon ...quest of the City of Baytown Chief Sanitarian or
his subordinate.
b),. An. offense under this section is a misdemeanor punishable by
a fine of 3200400.
Sec. 43-48. Authorized private sewage facilitie&
The Chief Sanitarian may grant a permit to use and maintain a
private sewage facility if:
`$oil and percolation tests required herein are accepted and
approved by the Chief Sanitarian; and
b) '`A :building permit was issued by the Chief Building Official
prior to construction and installation; and
c) :Aerobic or anaerobic sewage facilities are located on a lot
or tracts
0: at least 15,000 square feet in area;
whose ground water table is more than four (4) feet
below the bottom of the discharge trench;
3) outside of the "V1 -30" or "A1 -30" zones according to
the applicable flood insurance rate map; and
0 whose soil conditions, as shown by soil and percolation
tests conducted by a registered professional sanitarian or
registered professional engineer, are such that the system,
built within the limits set forth in Table V of the
construction standards, can discharge wastewater in subsoil
at a rate necessary to prevent discharge to the surface of
the ground, including. ditches, streams, ponds, lakes, bays, or
adjacent lots or tracts; or
d) A holding tank facility:
1). which uses a non - corrosive, watertight and airtight
tank; and
2) of at least 1,000 gallon capacity for single family
residence or commercial use; and
e) Such private sewage facility complies with construction
standards established herein; and
f) : The construction and installation passes inspection of the
Chief Sanitarian and Chief Building Official or their
subordinates.
Sec- 34-49. Enforcement.
a) The Chief Sanitarian and his subordinates shall be charged
with administering and enforcing the terms and conditions of this
Article and all other provisions of laws relating to private sewage
facilities.
b) The duties of the Chief Sanitarian shall include not only the
issuance of operating permits as required by this Article, but also the
responsibility of insuring that all private sewage facilities comply with
this Article and any other applicable laws, and that all private sewage
facilities for which a permit is required, do in fact have a permit. The
Chief Sanitarian or his subordinates shall make such inspections as may
be necessary and initiate appropriate action to bring about compliance
with this Article and other applicable law if such inspection discloses
any instance of noncompliance. The Chief Sanitarian or his
subordinates shall investigate thoroughly any complaints of alleged
violations of this Article.
c) The Chief Sanitarian or his subordinates shall have the power
and authority to administer and enforce the conditions of this Article
and all other laws relating to private sewage facilities. Included among
such powers are the following specific powers:
1) Every private sewage facility for which a permit is required
shall be subject to the inspection and approval of the Chief
Sanitarian or his subordinates. When deemed advisable by the
Chief Sanitarian, a private sewage facility may be inspected at
the point of manufacture if such point is within or adjacent to
the city.
C
C
1) Upon presentation of proper identification to the owner,
agent or tenant in charge of such property, the Chief Sanitarian
or his subordinate may enter for the purpose of inspecting and
investlgati -:- private sewage facilities, any building structure, or
other premises or property between. the hours of 8 a.m. -and 5
p.m,. Mondays through Fridays. Whenever the Chief Sanitarian or
his subordinate shall enter upon private property, under any
circumstances, for the purpose of inspecting and /or investigating
private sewage facilities which property has management in
residence, such management, or the person then in charge, shall
be. 'notified of his presence and shown his proper and official
credentials. Whenever the Chief Sanitarian or his subordinate is
denied admission ►:o inspect .any premises, inspection shall be
made only under authority of a warrant issued by a magistrate
authorizing the inspection for violations of this Article.
3) Upon notice and issuance of a stop order from the Chief
Sanitarian or his subordinate, work on any private sewage facility
that. is being conducted shall be immediately stopped. Such notice
and : order shall be in writing and shalt be given to the owner of
the, property, or to his agent, or to the person doing the work,
and . shall state the conditions under which work may be resumed.
Where an emergency exists, written notice shall not be required
to be given by the Chief Sanitarian. Following the issuance of a
stop order, the Chief Sanitarian shall initiate .proceedings to
revoke any permit issued for the work covered by such stop
order, consistent with subsection KQ of this section, unless the
cause of the stop order is resolved to the Chief Sanitarian's
satisfaction. A person commits an offense if he intentionally or
knowingly works upon private sewage facility for which a written
stop order was issued by the City of Baytown Chief Sanitarian
or: -his subordinate.
4),' The Chief Sanitarian shall have, and is hereby granted, the
power and authority to revoke any and all permits authorized by
this Article for violation of the terms and provisions of this
Article; provided that, the Chief Sanitarian shall conduct a
hearing prior to the revocation of any permit authorized under
this:<Article to determine the facts incident to the _pending
revocation. The person whose permit is under consideration shall
be given at least ten (10) calendar days' written notice of the
hearing and shall be permitted to present relevant facts and
legal- argument regarding the pending revocation. Following such
hearing, the Chief Sanitarian shall consider the merits of the
case and shall present his written findings of fact prior to any
action. Provided further, however, that if in the opinion of the
Chief Sanitarian, the health, safety or welfare of the citizens of
the city is endangered by any violation of this Article, the Chief
Sanitarian may immediately revoke any or all permits authorized
by this Article and shall conduct the necessary hearing as soon
as possible thereafter, but in no case later than three (3)
business days after the effective date of the revocation unless
the affected permittee shall request in writing a later date. .
5) Appeal of the denial or revocation of any permit herein,
shall be to City Council if written notice is given within ten
(10) days of the receipt of the Chief Sanitarian's written findings
of fact. No work upon nor use or operation of such private
sewage facility shall proceed until the conclusion of all appeals
thereunder.
6) The Chief Sanitarian shall have the authority to adopt
regulations required to implement the provisions of this section.
Sec. 34-50. Operating permit.
A) The application for a permit shall be submitted in such form
as the Chief Sanitarian may prescribe and shall be accompanied by
drawings and descriptive data to verify compliance with the provisions
® of this Article.
B) Existing private sewage facilities; operating permits;
1) After the date of passage of this Article, all private
sewage facilities then existing must receive operating
permits within one hundred eighty (180) days after the
passage of this Article.
•
n
L�
2) In order to receive operating permits, all private sewage
facilities existing ' an the date of passage of this _chapter. .;.
..must conform to the requirements of section 34-43, '34�4i6,
and '4-U when an operating permit is issued
3) Private sewage facilities previously constructed, or in
the process of being constructed in an unincorporated area
.and thereafter annexed by the city shall be considered : es
existing private sewage facility under this subsection;
provided, however, that the date of the first publication of
notice for a public hearing (as required by Section 6 of
Tex. Rev. Civ. Stat., art. 970a) regarding the proposed
annexation of the area wherein such private sewage.
facilities are located shall, for the purposes of this Article,
be considered the date of the applicability 4., this Article
to such private sewage facilities located in any area finally
annexed.
C) , Subterfuge. Any permit secured before or after the
effec w
te, date of this Article which, in the opinion of the Chief
Sanitarian, has been secured through subterfuge and not in full
compliance.
`with the provisions of this'Article'shall be revoked by the
Chief Sanitarian; provided that, such revocation shall conform with the
Provision's,.-of subsection 34-49 (cK4) regarding notice and hearing.
D) Permit fees shall be paid to the health department as
follows:
Private sewage facility operating permit. ..... $250.00
E) The applicant for a permit or holder of a permit shall not
be entitled to a refund of any fee paid in case the permit is revoked
or denied
F) , An operating permit for a holding tank facility is also
dependent, upon the furnishing of trip tickets provided by the permittee
and: the waste disposal carrier, detailing the waste disposal, including
name and 'location of the permitted facility, gallons per trip, gallons to
date by :calendar year and the name and location of the ultimate
disposal site. Trip tickets for the previous twelve (12) month period
shell be maintained at the site of the holding tank facility at all
times.
Section 2: All ordinances or parts of ordinances inconsistent with the
is of this ordinance are hereby repealed, provided however, that such repeal
shall be only
to
the extent
of such inconsistency
and in all
other respects this
ordinance shall
be
cumulative
of other ordinances
regulating
and governing the
subject matter covered by this ordinance.
Section 3: If any provision, section, exception, subsection, paragraph,
sentence, clause or phrase of this ordinance or the application of same to any
person or set of circumstances, shall for any reason be held unconstitutional, void or
invalid, such invalidity shall not affect the validity of the remaining provisions of
this ordinance or their application to other persons or sets of circumstances and to
this end all provisions of this ordinance are declared to be severable.
Section 4: Any person who shall violate any provision of this ordinance shall
be deemed guilty of a misdemeanor and upon conviction shall be punished by a fine
of not more than One Thousand and No /100 ($1,000.00) Dollars, or the maximum
provided.
�J
r
L_J
y
Section S: This Ordinance shall take effect from and after ten (10) days from.
its passage by the City Council. The City Clerk is hereby directed to give notice
hereof by causing the caption of this ordinance to be published in the official_
newspaper of the City of Baytown at least twice within ten (10) days after the
Passage of this ordinance.
INTRODUCED, READ, and PASSED by the affirmative vote of the City
Council of the City of Baytown, this the 13th day of December, 1984.
.s s /
MAWIYi3� �7•T`� �'�`�
11
i
•
Constructi
SI
Standards for Privat
age Facilities
v
11
TABLE OF CONTENTS
.001. General Procedural Rules
(a) General Environmental Requirements for Septic
Tank-Disposal Systems
(b) Authority of Texas Department of Health to
Regulate Private Sewage Facilities
(c) Relations With Other Governmental Entities
(d) Purpose of These Construction Standards
.002. Design Standards For Septic Tank Systems
(a) Definition of Terms
(b) Design Approval of Private Sewage Facilities
(c) Septic Tank Design - Residential
(d) Septic Tank Design - Institutions
(e) Selection of Proper Subsurface Disposal Methods
(f) Effluent Disposal Systems
(g) Percolation Test Procedures
(h) Septic Tank Maintenance
(i) On -Site Aerobic Sewage Treatment Plants for
Individual Residences
.003. Common Unsatisfactory On -Site Disposal Systems
(a) Cesspools
(b) Sore holes and Injection Wells
(c) Seepage Pits
3
3
5
6
7
6
10
15
17
17
30
33
ETr
35
36
36
r
U
11
Adopted By The Texas Board of Health
November 30, 1977
Formerly Published :;s "A Guide to the
Disposal of !:.- .;izshold Sewaj,e"
C _-,
.001. General Procedural Rules
(b) Authority of Texas Department of Health to Regulate Private Sewage
facilities
Article 4477 -1, Section 23(b), the Texas Sanitation and Health
Protection Law, Texas Civil Statutes, covers the Department of Health's
authority for promulgating construction rules and standards, and the
-3-
(a) General Environmental Requirements for Septic Tank Disposal Systems
(1) Background - These construction standards are being adopted under
_ authority of the Texas Sanitation and Health Protection Law,
Article 4477 -1, Section 23(b). The septic tank sewage disposal
system was originally developed to serge rural residences. =Fos
this purpose, the properly installed septic tank parforsed well
and permitted the remote rural resident to utilize the eonveatence
.
of indoor plumbing and toilet disposal. During the past twenty -five
years, the population distribution in the United States-b".sbifted'
from rural to urban, thus creating rapid development in and on' the
fringes of urban areas. Many residential subdivisions have been
located beyond the limits of organized water and sewerage facilities
and the residents must rely on individual resources available..nithin
the boundaries of small lots or tracts of land. Septic task systems
have been used frequently as the means of liquid waste disposal'.;
Unfortunately, in many cases, subdivisions were located in arena
with soil conditions unsuitable for septic tank systems. Quite
often, lot sizes are no larger than those found in subdivisions
serviced by central water and sewerage systems. Residential areas
with small lots served by septic tank systems on many occasions,
qw
are subjected to undesirable conditions such as widespread
saturation of the soil, malfunction of the septic tank systems,
sewage on the surface of the
g ground and in roadside ditches and
strained relationships between neighbors. The standards presented
herein are based on the cumulative observations and experiences
of the past and are intended to provide the citizens of this
State with adequate public health protection and a minimum of
environmental pollution.
(2) Locational and Environmental Standards - The developers of
subdivisions which are remote from organized sewage collection
systems should consider the method of sewage disposal in the
determination of lot size and arrangement. The provision of a
collection system and central treatment plant is generally the
�.
preferred method of sewage disposal. However, if soil conditions
permit and other factors are favorable to the use of septic tank
systems, the standards in Table I should be used with regard to
i
the location of the components of the septic tank system.
(b) Authority of Texas Department of Health to Regulate Private Sewage
facilities
Article 4477 -1, Section 23(b), the Texas Sanitation and Health
Protection Law, Texas Civil Statutes, covers the Department of Health's
authority for promulgating construction rules and standards, and the
-3-
11
•
C
TABLE I
MINIM SAFE DISTANCE IN FEET
Property Lines 10
* Septic tanks or holding tanks which are designed
for submergence (reinforced, monolithic concrete
o: equal) may be placed within 20 feet of streams,
ponds, water:well`s` and underground cisterns, pro-
vided the 'influent and effluent lines to and from
the tank are constructed using watertight sewer
pipe with compression or solvent welded joints.
** 150 feet is the minimum separation distance for
public water well's.
-4-
Soil
Sever Pipe
Septic
Absorption
With Watertight
From To
Tank.
System
Joints:`
Water Wells, Under Oda
Cisterns and Pump Section
Pipes
50*
100**
20
Public Water Supply Lines
5
10
5
Streams, Ponds and Lakes
50*
75
20
Foundation Walls of
Structures
5
15
--
Property Lines 10
* Septic tanks or holding tanks which are designed
for submergence (reinforced, monolithic concrete
o: equal) may be placed within 20 feet of streams,
ponds, water:well`s` and underground cisterns, pro-
vided the 'influent and effluent lines to and from
the tank are constructed using watertight sewer
pipe with compression or solvent welded joints.
** 150 feet is the minimum separation distance for
public water well's.
-4-
F-
•
u
Texas Water Code, Section 21.083, Texas Civil Statutes, directs the Texas:
Department; of Water Resources to consult with the Commissioner of Health
for recommendations concerning the impact of the use of septic tanks or
other prvate_ sewage facilities on public health before entering an
order regulating the installation' or use of such facilities in a given
area.
(c) Relations With Other Governmental Entities
(1) Texas Department of Water Resources - The state level responsibility
for the management-and control of septic tank practices is shared
by the Texas Department of Water Resources and the Texas Department
of Health. The.Texas Water Code, Section 21.083, Subsection (b),
defines the Department's authority as primarily of an area or
regional nature insofar as the control of pollution caused by
septic tanks. When the problems of a particular area are likely
to ,:produce hazards to public health through area -wide water
pollution caused by septic tank disposal systems, the Texas Water
Codd. gives the authority to limit the number and type of septic
tanks, prohibit the installation and use of additional septic
tanks and provide for the gradual and systematic reduction of
septic tanks in the area.
(2) Local Health Departments - The Texas Sanitation and Health
Protection Law, Article 4477 -1. Texas Civil Statutes, requires
local health officials to abate nuisances, and Articles 4427 and
4430, Texas Civil Statutes, requires local health officials to
aid the'State Board of Health is the enforcement of its rules,
regulations, requirements and ordinances and in the enforcement
of all sanitary laws within the jurisdiction of the local health
officials. Local health agencies may be required by city,
ordinance or septic tank control order to enforce regulations
which exceed the requirements of these standards, but local
authorities should not permit their standards to fall below
those recommended by the Texas Department of Health. Local
regulations shall be reasonable and, if technical in nature, must
be based on sound engineering principles.
(3) River Authorities and Water Districts - River authorities or water
districts may assist in water pollution control enforcement
procedures through orders issued by the Texas Department of Water
Resources to control or prohibit the use of septic tanks in an
area. The Department of Water Resources may delegate them as the
licensing authority to develop procedures concerning administration,
inspection, issuance of licenses and enforcement of a Texas
Department of Water Resources Order.
-5-
•
C
(4) County Commissioners Courts - Section 21.084 of the Texas Water
Code empowers the Commissioners Court of any county to adopt a
septic tank control order controlling or prohibiting the
installation or use of septic tanks in any area of a county
under its jurisdiction. The Texas Department of Water Resources
must grant its approval of the adopted county order prior to its
becoming effective. The order includes construction standards
promulgated by counties which may be adjusted to local conditions
so long as they do not fall below the standards of the Texas
Department of Health and also provided that the adjustments are
reasonable and, if technical in nature, are based on sound
engineering principles.
(S) Municipal Corporations - Cities, towns and villages may control or
prohibit the use of septic tanks by local ordinance. The
standards set forth in any such ordinance should not fall below
those stated in this publication, but these entities may establish
standards which will produce a higher quality of operation, provided
the standards are reasonable and, if technical in nature, are based
on sound engineering principles.
(6) Regional Councils of Government - These agencies are principally
created to establish and execute the planning process in a region
designated by the Governor. (Article 1011m, V.T.C.S.). The
regional councils may contribute to the effective and proper
disposal of sewage by (a) guiding developers to the more
favorable alternative of sewage collection systems and centralized
sewage treatment facilities, (b) preprXing soil maps showing
favorable, intermediate and unacceptable locations for sewage
treatment systems dependent upon subsurface effluent disposal,
and (c) assisting local governments in recognizing the need for
regulatory devices for sewage disposal.
(d) Purpose of These Construction Standards
The primary purpose of this undertaking is to establish standards for
constructing private sewage facilities. The construction standards
will cover the aspects of sewage disposal which deal with on -site
treatment facilities for use by individual homes, small business
establishments, recreational areas, institutions and other activities
that conform to Rule .002(a)(2) and do not have access to a central
collection system. The various types of treatment processes covered
by these standards do not have any open discharges to the surface of
the ground. Any process which proposes - surface discharge should be
designed in accordance with the Department of Health /Department of Water
Resources' "Design Criteria for Sewerage Systems," and must be operated
under a waste control permit issued by the Texas Department of Water
Resources.
-6-
-002. Design Standards for Septic Tank Systems
(a) Definition:of'Terms
(1) Sewa e - Any wastewater containing animal or vegetable matter
in suspension or solution, including liquids containing chemicals
in solution, domestic wastewater, and laundry wastes. (Used
interchangeably with the term wastewater,)
(2) Private Sewage Facilities - Facilities provided to serve only an
individual household, multiple unit residential structures or
LN
commercial establishment within a designated area and whose
operation 'and maintenance is the sole responsibility of the
householder or owner of the establishment's facilities. Such
facilities provide for the disposal of treated wastewater by
subsoil absorption, evaporation or evapotranspiration and are
not.subject to the issuance of wastewater discharge orders by
the Texas- Department of Water Resources.
(3) Septic Tank - A watertight, covered receptacle designed and
constructed to receive the discharge of sewage from a building
sewer, separate solids from the liquid, digest organic matter
under.anaerobic conditions and store digested solids through a
period of detention, and allow the clarified liquids to be
disposed -6f in an acceptable manner.
(4) Sludge - The accumulated settleable solids deposited from sewage
and containing more or less water to firm a semi- liquid mass.
" (5) Scum - A mass of sewage matter which floats on the surface of
sewage.
(6) Subsurface Sewage Disposal System - A system for the disposal
�'. of the 'effluent from a septic tank or other facilities
providing for soil absorption, evaporation or evapotranspiration.
(7) ,Cessaool - A covered structure having walls with open joints
which receives the discharge of raw domestic sewage or other
organic wastes and is designed to decompose to a limited degree
the organic matter and solids, but permit the liquids to seep
through the bottom and sides.
(8) Soil Absorption System.- Any system that utilizes the soil for
subsequent absorption of the treated sewage, such as an absorption
trench or absorption bed.
(9) Evapotranspiration System - A subsurface system which utilizes
surface evaporation and plant transpiration to permit disposal
of effluent from wastewater treatment facilities.
(10) Seepage Pit - A covered excavation in the ground which receives
septic tank effluent, and is so designed to permit the effluent
receiving prior treatment to seep through the bottom and sides
of the excavation.
-7-
•
El
(11) Holding Tank
an: anai
treatm
(12). Inject
- A tank used to receive and store sewage wastes in
condition until its ultimate disposal to an approved
cility.
1 - A hole drilled into permeable soil some distance
surface into which raw or treated sewage effluent
is discharged.
(13) Bore Hole Same as an injection well.
(b) Design Approval For Private Sewage Facilities
(1) Approval of :_Conventional Designs - The construction standards
contained herein are promulgated under authority of the Texas
Sanitation and Health Protection Law, Article 4477 -1, V.T.C.S.,
Sections 23(b), 24 and 25. In addition, Section 5a of this
statute states that the disposal of human excreta in populous
areas must :be by methods approved by the Texas Department of
Health: and Section 5b states that effluent from septic tanks
shall'be disposed of through subsurface drainfields designed in
accordance with good public health engineering practice. The
following design standards constitute the minimum criteria
established and approved by the Texas Department of Health for
methods of.-on-site sewage disposal which are consistent with good
public health engineering practice.
(2) Approval.of Innovative Designs - Agencies vested with the
responsibility of enforcing septic tank regulations are encouraged
to use feasible innovative designs which are not specifically
covered in;; his construction standard. Texas is a large state-
with many different types of topographical, geological and
climatic conditions. New systems may be conceived in the
future to meet requirements demanded by these conditions and the
systems,maye differ from the specific construction methods outlined
in this publication. The use of innovative systems is encouraged,
however, to both assist local regulatory agencies in determining
the reliability of a new system and protect the public from
improperly.designed systems, the Texas Department of Health
will review and evaluate new systems on an individual basis.
Systems found to be designed in accordance with good engineering
practice will be approved by the Texas Department of Health.
(3) Approval of Proprietary Systems - All new systems which deviate
significantly from these construction standards should be reviewed
and approved by the Texas Department of Health prior to their
installation and use. Notice of disapproval by either the Texas
Department of Health or the local regulatory authority should
prevent such facilities from being installed. Categorical approval
of proprietary systems will not be granted by the Texas Department
of Health.
-8-
�J
11
(4) Residential Lot Sizin
(A) General Considerations - The failure of a septic tank system
may be caused by a large number of circumstances, including
inadequate soil percolation, improper construction, design,
installation and misuse. The single most important factor
concerning public health problems resulting from these
failures is the residential dwelling density which is strictly
a function of lot-size. The failure of a septic tank system
in highly populated areas is the fundamental cause of public
health hazards resulting from on -site sewage disposal.
Surfacing sewage provides•a medium for the transmission of
disease and the fact that many people are in the vicinity
cause'concern.over the spreading of disease. Septic tank
systems using soil.absorptiou for effluent disposal are more
prone to malfunction in high population density situations
because the soil available to absorb or evaporate the effluent
is limited. The failure of an absorption system on a small
lot can be financially disastrous to the owner because the lot
may not contain sufficient room to construct a new absorption,
field in a new location.
(B) Platted Subdivisions Served by Public Water Supply - Platted
subdivisions of single family residences served by a public
water supply but utilizing individual subsurface absorptive
methods for sewage disposal should provide for individual lots
having surface areas of at least 15,000 square feet.
(C) Platted Subdivisions Served by Individual Water Systems - In
platted subdivisions for single family residences where each
lot maintains an individual water supply well and septic tank
with a soil absorption system, the plat should show the approved
well location and a sanitary zone around the well within a
100 foot radius in which no absorptive type septic tank system
may be constructed. The well should be constructed in
accordance with recommendations of the Texas Department of
Health guide for private water well construction. A watertight
septic tank may be placed closer to the water well than 100
feet, provided the minimum separation stated in Table I is
not violated. To minimize the possibility of the transmission
of waterborne diseases due to the pollution of the water
supplied for domestic use, each lot in a platted subdivision
should not contain less area than 20,000 sq. ft.
(D) Mobile Home Sites - Mobile homes permanently located on
individual lots and individually owned should comply with the
recommendations stated in Rule .002(b)(4)(A). Mobile home
parks which are owned by an individual and which rent or lease
space to transient residences may utilize smaller lots than
stated in Rule .002(b)(4)(B), provided an overall sewerage
plan is submitted to the appropriate authority for approval,
and water is supplied by a public water system. Parks of this
®
-9-
v
i
type may connect more than one mobile home or trailer to
a single septic tank system, provided the system is
designed to treat the total anticipated sewage discharge
from.the connected homes and the sewage facility conforms
to ,Rule .002(a)(2). Any other type of facility which
combines more than one dwelling's sewage is not considered
to be a private facility and a permit may be required by
the Texas Department of Water Resources.
(c). Septic Tank Design Standards - Residential
(1)
House Sewer - The sewer from the house plumbing system to the
septic tank should be constructed of structurally sound pipe
such aa.;cast iron, or approved types of plastic pipe. Cast
iron or 'high strength pipe should always be used under
driveways. The pipe from the house to the septic tank should
have a minimum inside diameter of not less than 3 inches and
be.compatible with the house stub out pipe. The slope of the
house sever should be no less than 1/4 inch fall per foot of
pipe. The stub out location should be at the highest possible
elevation with respect to the house foundation to prevent deep
septic tank systems. The line must be of watertight
construction.
(2)
Septic Tank Capacity Based on Sewage Loading - A properly designed
septic tank should be watertight and should be of a capacity equal
to the flow of sewage from the facilities being served for a two-
day period. The settleable and suspended solids will undergo
partial decomposition under anaerobic conditions. As a result
of use, the septic tank will accumulate partially decomposed
solids which must be removed periodically. As additional sewage
is introduced into the tank, partially clarified effluent is
discharged into the subsurface disposal field. It is very
important that the septic tank be made large enough to accom-
-
modate a two -day sewage loading. The best method of estimating
a tank's sewage loading is based upon the number of bedrooms
in the house. Table II should be used to determine the required
minimum septic tank liquid capacity.
(3)
Inlet and Outlet Devices - To assure rapid drainage of house
plumbing, the flow line of the inlet pipe should be 3 inches
higher than the operating tank liquid level which is determined
by the flow line of the outlet pipe. Liquid penetration of
the inlet device should be at least 6 inches, but never greater
than that of the outlet device. Liquid penetration of the
outlet device should be approximately 40 per cent of the tank
liquid depth. "T" branches are recommended for inlet and outlet
devices because they provide a means for venting the gases
produced by the decomposition process from the tank and absorption
-10-
- 11 -
r
1
nl k
4
y I
TABLE II
.SEPTIC TANK MINIMM LIQUID CAPACITY
Septic Tank Capacity
Dumber cf Bedrooms (Gallons)
Two or less 750
Three 1,000
Four 1,250
For each additional 250
NOTE; The Inside Depth-Of The'Tank Should hot Be Less
Than Four Feet.
See Table V For Calculating The number Of Bedrooms
Based On Dwelling Living Area.
- 11 -
v
17-�
-12-
y
.t
4
system through the house plumbing. Otherwise, gases may escape
from around the lid
of the tank and cause as odor nuisance in the
vicinity.of the septic tank. "T" branches
4
also offer ready sccess
for required maintenance. To prevent the escape of floating
solids from the tank to the subsurface disposal field and the
poss.ibiltq of inlet stoppages, the open spaces between the tops
of the inlet
i
and outlet devices and the underside of the tank
cover should not be
greater than 2 inches. (See Figure l) In
order to - provide a good watertight
septic tank, the inlet and
outlet "T ";branches should be installed in a
l`
permanent manner
at ahe time the septic tank is constructed. Factory built tanks
should have•the "T"
branches grouted in place before delivery so
that the only connections
to the tank at the point of installation
will be the influent and effluent lines.
(4) Details of:Seotic Tank Design - A properly designed singie-
compartment tank will give acceptable performance. Recent
research studies indicate that 2 tanks in series or a two -
compartment tank, with approximately 1/2 to 2/3 of the total
volume in the first
compartment, will provide an extra degree of
solids removal, which is especially valuable under
poor soil
conditions; The second tank or compartment should have inlet
'devices
and outlet designed the same as for a single - compartment
tank, except
that the elevation, or flow line, of both inlet and
outlet devices in
the second unit should be the same as the
outlet device in the first unit. (See Figure 2.) A
port shall
be provided to each compartment for inspection, cleaning and
maintenance'. Both the inlet and outlet devices should be
accessible for inspection and maintenance without having to
enter the septic tank. For tanks not buried too deeply, the
use of sectional slab covers will conveniently and safely
provide the
needed access. For tanks buried deeply, manholes
with risers
are recommended. The septic tank should be of sturdy, ='
watertight construction. Materials used may be reinforced
concrete. poured in place, precast concrete, fiberglass or
other materials approved by the regulatory authority. Metal
septic tanks are not recommended because they are extremely
subject to
corrosion. The septic tank should be structurally
designed to resist buckling from
external hydraulic loading
and exterior loadings caused by earth fill, garden tractors
or other heavy vehicles. The tanks shall be tested by
filling with water 24 hours prior to installation and checking
at the time of installation for leaks and structural integrity.
Tanks exhibiting obvious deflections
or leaks should not be
installed. Where concrete tanks are installed,'sweating or
seepage at construction joints is acceptable, provided the tank
structure contains no open cracks or large voids.
-12-
LJ
El
Ei
•
L 11
11
� li
(d) Septic Tank Design - Institutions
(1) General Consideration.of Use of Septic Tank System - Septic
tanks may be used as a means of sewage disposal for non -
residential activities. Howev %r, experience indicates that the
usefulness of the septic tank system decreases as the size of
the establishment served increases. When a septic tank is being
considered for service to an activity that will produce more
sewage than a single family residence, design guidance should be
obtained from a local health department, regulatory agency or a
consultant who is professionally registered as an engineer or
sanitarian in Texas.
(2) Sewage Loadinst - The total quantity of sewage applied per day
to the septic tank provides the basis for the determination of
its size. Table IV, entitled, "Individual Usage Rate,"
will be of assistance in estimating the daily sewage flow per
capita for a, variety of living and activity situations.
(3) Compartments to Be Provided - Although single - compartment tanks
are acceptable for single family residences, tanks with 2 or
more compartments should be provided for large institutional
systems. The compartments should be separated by walls with
tees or ells to permit liquid flow. The flow line of this
intermediate fitting should be at the same elevation of the flow
line of the outlet fitting, i.e., 3 inches below the elevation
of the flow line of the inlet fitting. The capacity of the
first compartment should be at lee I or 2 times the capacity
of the second compartment.
(4) Selection of Septic Tank Capacity - The net volume or effective
capacity below the flow line of a septic tank for flows up to
500 gallons per day should be at least 750 gallons. For flows
between 500 and 1,500 gallons per day, the capacity of the
tank should be equal to approximately 2 days sewage flow. With
flows greater than 1,500 gallons per day, the minimum effective
tank capacity should equal 1,125 gallons plus 75 per cent of the
daily sewage flow, or
V = 1,125 + 0.75 Q
Where Q is the average daily flow in gallons
per day and V is the tank volume in gallons.
For daily flows over 5,000 gallons per day, consideration should
be given to other types of treatment units. More technically
advanced processes will probably be more economical than the
septic tank for flows in excess of 5,000 gallons per day.
-15-
r�
U
El
p.:.
i
is
i
TABLE IV
INDIVIDUAL USAGE RATE
This table may be used for estimating gallons of daily sewage flaw
per person, to determine minimum tank capacity requirements.
TYPE OF ESTABLISHMENT GALLONS/PERSON/DAY
Apartment houses ......... ...............................
75
Townhouses (with clothes washer) ........................
100
Motelsand Hotels ......... ...............................
60
Restaurants .............. ...............................
15
Trailer and RV Parks...... ..... ..........................
50
Work or'construction camps (semi - permanent) ..............
50
Youth camps (no meals served ) ............................
15
Schools.without - cafeterias, gymnasiums or showers........
15
Schools with cafeterias, but no gymnasiums or showers ..•.
20
Schools with cafeterias, gymnasiums and showers..........
25
Boarding schools .........................................
100
Office Buildings .......... ...............................
15
Hospitals .................................. ...... .....
200
Institutions other than hospitals ........................
100
Factories (gallons per person per shift,
exclusive of industrial wastes) .......................
20
Parks without bathhouse ... ...............................
5
Parks with bathhouse.. ...... ...........................
10
Swimming pools_ and bathhouses ............................
10
.Country clubs (per resident member) .....................
100
Country clubs (per non - resident member present) ..........
25
Drive -in theaters (per car space) ........................
5
Movie theaters (per auditorium seat) .....................
5
Airports (per passenger).. ...... .........................
5
Self- service laundries (gallons per wash,
i.e., per customer) ...................................
50
Stores (total per day per washroom)..., ..................
400
Service stations (per vehicle served) ....................
10
-16-
E
E
(e) Selection of Proper Subsurface Disposal Method
(1) In designing a septic tank system, several options concerning
subsurfac.;disposal are available. Chart I has been prepared
to aid; >in the selection of the proper system based on lot size,
percolation rate and economic considerations. The chart includes
the three systems recommended for subsurface disposal which are
drainfields, absorption beds and evapotranspiration beds. The
purpose of'the chart is to give the reader a general idea as to
the most feasible type of system to construct taking into
consideration lot size, soil absorptive capacity, and volume
of soil .removed or relocated.during construction.
(2) 'After sizing an appropriate septic tank, the installer should
calculate what bottom area will be required for a trench system,
an absorption bed system and an evapotranspiration system.
Generally, the system having the least number of square feet
of bottom area will be the most economical. In most cases
where adequate room is available, a trench system will be the
least costly.
(3) In areas where soils have low permeability, it is possible to
design a system which combines both soil absorption and
evapotranspiration. Such systems are somewhat complicated
and will not be discussed in this text; however, additional
information is available at the Texas Department of Health
Division of Wastewater Technology and Surveillance.
(f) Effluent Disposal Systems
(1) Soil Absorption System - General Consideration - The effluent
discharged from a septic tank requires further handling to render
it safe from a public health standpoint. A well- designed
subsurface soil absorption system will allow these liquids to
seep into the ground without creating a health hazard or nuisance..
After the prospective builder has selected a suitable area and
assured himself that safe distances from wells, lakes. etc.
can be maintained, he should then determine whether soil
formations in the selected area will allow a soil absorption
system to work. The single factor of prime importance in the
design of a soil absorption system is the percolation rate. The
percolation rate determines the amount of drainfield that must be
installed to dispose of the septic tank effluent. If the
percolation rate falls below the accepted minimum level, another
method of sewage disposal must be found. When soil absorption systems
are used, there should be no interference from ground water, and
the ground water table should be located at least 4 feet below the
bottom of the trench. In the coastal areas of Texas, salt water
may occur at depths less than 4 feet. If the soil above the salt
-17-
C,
El
C
O
L
b
L M
U r•1
•+ a at
e w p0
o u
V O
a
c
W
y
O
PA
U3
H
Q
kf
pV
OG
O
H
W
H
a
w
a
H c
xF a.
V
z
U H
H
U
w
a
w
a
O
w
H
w
w
x
y
O
F
y
W
C9
co
w
-18-
-o
L �
u o
o�
4 W
L
W •rl
C eti
O 1.+
UD
a
x
e
.r as
^l H
aD
y
W c
C +�
H -O
.•l
O
v4
O W
C -O
O al
u
+� H
b O
C W
al +�
W f+
O al
S
U O
a�
o.
x
+l C M
3 d O
O 'C
O Qr x
to d
CH A+
L O a
O d m 3
a 0 c aL+
al w 'fl W
0 w
.•i G W
+1 ea al W
a3
u 1 -p v
> ..a u
�Oaow
w
5
Ll
water is,shown to have good permeability, an absorption system
may be .installed and the above separation requirement disregarded.
The design standards for soil absorption systems set forth in
this publication are based on the premise that impervious strata
are at depths greater than 4 feet-below the bottom of the
absorptioa.trench. Conventional soil absorption systems should
not be used if either impervious strata or ground water exist
at depths less than 4 feet from the trench or bed bottom.
(2) Absorption Field, Level Terrain
(A) Absorption Field Sizinst - Where the topography or ground
slope is not too steep, a flat or level system of gravel
filled trenches or percolation beds is recommended. The
use of a looped trench system will avoid dead ends and
assure maximum effective utilization of all portions of
the system. The capacity of any particular absorption
system is fixed by the total area of trench or bed
bottom built into the system. The amount of this required
minimum area will depend upon the expected sewage load
and the average soil percolation rate. The soil percola-
tion rate may be determined by performing a percolation
test as described in Rule .002(8) of this pamphlet.
The trench dimensions may then be calculated from Table V.
(B) Absorption Field Construction - All parts of the trench
or bed bottom shall be at the same elevation. Trenches
should be constructed as shallow aw passible with a
minimum depth of 18 inches and a maximum depth of 36 inches.
For trench depths greater than 24 inches, sand should be
used to fill the trench up to the topsoil cover as shown
in Figure 4. The trench width should not exceed 30 inches
and narrow trenches (12 to 18 inches) are recommended.
Although trench length is based on bottom area only,
sidewall area is important since much of the wastewater
is absorbed through the sidewalls and is evapotranspirated.
Minimum recommended spacing between adjacent edges of
parallel trenches is approximately 5 feet. Liquid from
the septic tank is conducted to the absorption system via
a watertight line similar to the house sewer. The liquid
is distributed uniformly through the gravel - filled trenches
by the use of a perforated plastic pipe or equivalent pipe
materials. It is important that the distribution piping
be laid level in the trenches, with a minimum of 6 inches
gravel depth under the pipe and a 2 inch gravel cover.
Thus, a total gravel depth of approximately 12 inches would
be required. The trench media may be clean graded gravel,
broken vitrified brick, washed rock, crushed stone or similar
aggregate and may range in size from 1.5 inches to 2.5 inches.
Oyster shell, other types of shell and soft limestone are
not recommended for trench media because cementitious
-19-
Ll
I
> txi
N
,r
z
� O
w
H '►+
a
a
f+.
a
C
1"1
A
N
a
N
> txi
ar
,r
u
� O
N
H '►+
N
f+.
a
C
H
J
d
a
O
+t
W
CO
a
O
rI
I
Y w
o �
s0 i-► d
C w e O
d x
H o' 0 6
to 0
E v C 0 b+
o
CIO
c a < m
b
w w
d O U
N
N
v
C t�tl
O D
L
� Y
-4 ed w
-4 a
a - In
a L m
a°1D a o
3 �
d O
N V'
v .
0
Yn
aG u
C
� O 04
Owi ttdd u
O C
Owl v
Ad
d
'e
a
ar
I O O O O d
A
N
••1 N N 10'1 a
Y
O
z
0
w
6
u u
a In
a? d
.°+ i1
L Q L
as o 0 0 111 o W
ecd M N 1'01 Ln � 0 Q
►+ 00,
Ai co
mw
W
u
Q
N
>. >►
-.1
d c o =4 -•
W r7 U U a cl
t7 C C .L+ U
to
G) In N U
O O
4.—
Aj so. O n O OD %D r+
at d
w V N .a O O O
O o V
0 0
F U
LM 0 V
W m .4 � O
. �D No .+ %0 A
.4 /h s
-20-
u
ar
,r
u
OOA
OD
L
d
O
+t
L
dJ
w
m
W
O
u
3
w
w
L
L
d o
u
0
Y
0
w
E
rJ
E
b
b 7
wo
an
u
d
►+
3 o aoi
3"4
o
G
41
w 0
Id
wsu
0 s
w
Lewd
+i w
d
O L
u 41
10
co
L y
OW<
a.
ai
u
go
u E
a0i
>
aO+ a 1
O
w
..d tt
w 1
ai
'o w
en
0 lu
- Li
w 0
•:i
sO. r
=ww
.0 aai
m
o x
1 w 0
m
O w
.00
M 10+
O
u u
u
O A.
11 O O
w
OD ed
0%
u C
awi
O
cr co
L
m
.�
.r
"4
O .O
-CIO
O L r1
u a
•+
v
o ++
-4 m
r1
0 W
to • .+
co
O
W
•
W •
s0+
.� '00
0
co
to
'0
a w
o v
% .e to u
to O
Ol
•-t
y to
CD d
Id w
x
O O m
0
ld co
�:
d cd
Y W
d O
E 0
.0 c
m
a
O w
L
+f N
u •C
C m
C G
U
1d
V d
•-t
OD
to
Oi
u E
aAi
r. 0
Y
C D
I w
'o
w
d 'v
•-�
ww
co
z
E "r
EE
6 'O
.d Owl
O w
G -+
+O+
O
E
cd .
3 w
C
C7
C
Clay - Smaller than 0.002 mm diameter
Silt - 0.05 to 0.002 mm diameter
Sand- 2.0 to 0.05 mm diameter
• ID
�o
Be
6D
s°
70
CLAY
n
s
9k�e SILIT
C 'T 41
� =o suer /
CL A
30 LOA11 SILTY CLAT so
SANDY CL AT
LOA / o
2O
e
L AM
ISANOT LOAM SJJT LOAM Aft
i� Sll
LO ANY o0
SANG , SA D
pp .Op Bp �p �p Jp sp Jp ep p
PEIICENT SAND
i •
Chart II
Proportions of sand, silt and clay for different soil textures.
® U.S. D.A.
-21-
v
v
C
properties of this type of material often result in early
trench failure. The distribution pipe should consist of
plastic perforated pipe or equivalent materials with an
SDR ratio (ratio of pipe thickness to diameter) no greater
than 41. Normally, 4 inch diameter pipe is used for
drainfield construction, however, the diameter may range
from 3 inches to 6 inches and yield satisfactory results.
Jointed tile is not recommended for use because of the
difficulty in maintaining joint spacing and keeping the
line level. Covering of straw, butcher paper or similar
decomposable material over the top of the gravel is also
recommended to prevent the soil or sand backfill from
invading the gravel until the backfill becomes stabilized.
Tat, "per or other impervious material should not be used
under any circumstance. The pipe selected for drainfield
construction should have sufficient strength to resist
crushing from external loadings such as automobiles, yard
tractors and earth moving equipment. In no case shall
bituminous fiberboard or paper pipe (Orangeburg or similar
designations) be used anywhere in the septic tank system.
Poor construction practices will cause serious damage to
the soil absorption system. It is extremely important
that care be taken to avoid sealing the surface of the
bottom and sides•of the absorption trenches through
smearing. Trenches or beds should not be excavated
8 when the
soil is sufficiently wet so as to smear or compact easily.
All smeared or compacted surfaces occurring during construc-
tion should be raked to a depth ,,f 1 inch and loose material
removed just before the gravel or other media is placed.
(3) Absorption Field, Irreaular Terrain
(A) Absorption Trenches - Where the topography or ground slope
is too steep for feasible construction of a closed -loop
trench system, the following alternate layout may be used.
A single, level trench, constructed like the closed -loop
trench, is built along a contour and the overflow from
this line is conducted via a watertight line through
undisturbed soil to the next lower level, where a second
trench can be built along a contour similar to the upper
trench. The pattern can be repeated until the required
minimum trench bottom area has been provided. It is
recommended that no individual trench exceed 100 feet in
length. This technique is graphically illustrated in
Figure S. Other details of trench construction described
in Rule .002(f)(1) and shown'in Figure 4 should be followed.
-23-
E
ni
a 0
.d Da4
Use Compacted. Soil
Between Trenches
FIG. 5 SEPTIC TANK SYSTEM FOR SLOPING GROUND
-24-
rI
L-A
v
u
Id
A
(8) Soil_ Absorption Beds - In addition to the trench -type
absorption field, an absorption bed, as detailed in Figure 6,
may be. used in areas where the combination of soil percolation
and lot size precludes the use of a trench -type system with
minimum spacing between trenches. While absorption beds
require more bottom area than trenebes,.they tend to be more
compact since 5 feet of spacing is required between trenches.
The bed :shall be constructed with a depth ranging from 18
inches to 36 inches. The bed should be kept as shallow as
possible.(18 minimum depth) to promote aerobic bacterial
action in the soil and the bottom of the bed should be level
for uniform wastewater distribution. Six inches of 1.5 inch
to,25 -inch media (gravel, crushed stone, etc.) shall be
placed on the bed bottom followed by two or more distribution
pipes spaced 3 to 4 feet apart and 3 feet from the edge of the
bed. The distributor pipe is then covered with additional
gravel to a depth of approximately 2 inches. Since the pipe
is. approximately 4 inches in diameter, the total depth of
giavel•ia the bed will be 12 inches. The gravel should then
be-covered with a decomposable material, such as butcher
paper, to prevent the final soil layer from invading the
gravel 'and reducing porosity. The next soil layer should
consist of sand, sandy loam or a mixture of the two. If
clay, rock or other semi - impervious material is excavated
from the bed it should be removed and under no circumstances
be us4- to backfill the bed. Sand or sandy loam will provide
a capillary medium to help eliminate some of the wastewater
through evapotranspiration Rule .002j)(4). The bed should
be filled to within 3 inches from the top with sand or sandy
loam and mounded with sandy loam so that the center of the
bed is approximately 4 inches above normal ground elevation.
This will provide drainage away from the absorption bed.
(C) Absorption Bed Sizing - When this system is used, the absorption
bed area may be calculated using the following formula:
For Dwellings:
A = 300 (1 + B)
R
a
Where
A - The total absorption bed area
B = The total number of bedrooms in the dwelling
Ra= Sewage application rate for absorption trenches
(gal /sq. ft. /day) based on percolation rate.
(See Table V)
-25-
11
lwi
s.
6" min
12" max
Do not use rock or clay
tSA.dDY OAM/
for backfill
-SAND
•
36" s , .v •� o'o! 4 Paper
12"
4'
FIG. 6 ABSORPTION BED SYSTEM
-26-
E
For Icon- Residential Institutions:
A--31 L
R
a
Where
Daily wastewater discharge from institution (gal /day).
(4) Evapotranspiration Beds
(A) Use.of Evapotranspiration Beds - Evapotranspiration bed
systems may be used in locations where soil conditions are
not suitable for any type of soil absorption system. The
construction of an evapotranspiration bed is similar to an
absorptive system except two beds are required with a control
valve to divert wastewater from one bed to the other.
(B)• Evapotranspiration Bed Construction Features - Beds are
coast-
Tu
cted in impervious soil or soil with very high
absorptive capacity. When the soil has a very high absorptive
capacity (Glminute /inch) liners must be constructed to guard
against the possibility of wastewater discharging through the
soil (fissured rock or gravel) and contaminating streams,
lakes or shallow ground water. Impervious liners may consist
of concrete, hot mopped asphaltic membrane, plastic reservoir
liners or other approved pit lining materials. Liners are
not required in impervious soils and should not be used since
some of the wastewater may be absorbed in the soil and reduce
the overall evapotranspiration load. An evapotranspiration
system should be designed using the following parameters:
(i) Beds may be designed in any configuration (square,
round, etc.) but the total number of square feet
of bed area must be determined by the formula in
Rule .002(f)(4)(C).
I-
(ii) At least two beds must be constructed with valves
arranged to allow the effluent from a septic tank
to alternate between each bed. When one bed becomes
saturated (top of bed remains moist) the valve is
opened.to allow effluent to flow into the alternate
bed.
(iii) The beds should be constructed as shallow as possible
with a depth ranging from 18 inches to a maximum of
24 inches. This is necessary to keep the beds
aerobic and prevent clogging.
(iv) Rock media is placed on the bed bottom to a depth of
12 inches or less depending on the overall bed depth.
(If a liner is used which is subject to puncture, sand
should be placed on both sides of the liner.)
-27-
C]
L`
(v) The distribution pipe is centered in the rock
media and adequate pipe must be provided for uniform
distribution of effluent (4 feet maximum separation
between pipes and no less than 3 feet separation
between bed walls and the pipe). The bed bottom and
the pipe must be level.
(vi) A decomposable barrier (butcher paper or other non-
treated paper) is then placed over the rock and sand
is added to fill the bed to within 2 inches from the
top.
(vii) In_order to provide continuous capillary action in the
sand, "wicks" should be incorporated in the rock media.
Meld "Are simply sand structures which penetrate through
the rock media to the bottom of the bed (See Figure 7).
The total "wick" area should be 10% to 15% of the bed surface
area and should be uniformly spaced throughout the bed.
"Wick's" may also be constructed by simply grading furrows
in the rock media in between the distribution pipe. In
areas "of the State where rock media is expensive or -
difficult to obtain the total amount of rock may be
reduced by filling the initial 12 inches of the bed with
coarse sand (2.0 mm) and placing rock media only around
the top and bottom of the distribution pipe to form a 12
inch-to 18 inch enclosure.
(viii) After the sand is in place, the final ? inches of bed
volume is filled with topsoil and mounded so that the
center of the bed is at least 8 inches higher than
the edge.
(ix) Final bed construction consists of covering the surface
of the bed with grasses having good transpiration
properties.
(C) Bed Sizing - The-bed area may be calculated by using the
following formula:
A s 31,000 (1 + B)
EA
Where A - Total area of both beds (To find
one bed area divide A by 2)
B = Total number of bedrooms (B=2 for
minimum residence)
EA= Local pan evaporation rate in inches /year
(See Table VI)
0 -28-
E
E
E
•
. •nl O. C 'p
•� YC4 d d d
N ++ L
14 to
� < 7
� � U
i
N
d
N
-29-
sw
'cdeo"e0
.0 N •p W �
Y V r Aj Y
d 61 W
c ., .. O
,r �+ ,r m
ev CL .•a
Ai
E O
'OWN
cc v acid Ai
E d N PC .D 3
Ai .4 W 0
C O s0 C
M
1+ ai a1 ep
CI C ,'7 $w M
e� ++ E 4
E w Tj M 7.�i 'E L
W 7 PC O 7
u
+' Z �-4 E u c.
ns o u .a -w
►. vs L .. c M 0 Id
0.0 4j
Je>v0H0
O Y .0 4) L ,7
w u d d
> W m e�� o
O a$4 >% .4 C
o=
y O 0 W .O
7 t0 E 6C 'O
-+ O O W O O
jj
H C N tJ N
CJ M v1 C
••C +
+ •0+ d E O+ u
r L 7 0 eD
aJ N . 4 Y.1
M L 7 O L
a•r u"� y
W V h
0 m 0 C 0
3 Lo 0 u F
.••� N P1 S
L/1
k7
0
Z
a
,
♦
T
4Y1 0
y
e
u
V1
:. X12 !
a
Id
,
'z
C6
ea
Ole
IN
w
07 y�
Y 6
(Q'
Qi is
�t.
.• �
V!
z
<
w
a
b
U
H
OG
O
ir+
H
I
w
i
'i
I
4c
z
l6
�i
7
f
Aj
u 0
. •nl O. C 'p
•� YC4 d d d
N ++ L
14 to
� < 7
� � U
i
N
d
N
-29-
sw
'cdeo"e0
.0 N •p W �
Y V r Aj Y
d 61 W
c ., .. O
,r �+ ,r m
ev CL .•a
Ai
E O
'OWN
cc v acid Ai
E d N PC .D 3
Ai .4 W 0
C O s0 C
M
1+ ai a1 ep
CI C ,'7 $w M
e� ++ E 4
E w Tj M 7.�i 'E L
W 7 PC O 7
u
+' Z �-4 E u c.
ns o u .a -w
►. vs L .. c M 0 Id
0.0 4j
Je>v0H0
O Y .0 4) L ,7
w u d d
> W m e�� o
O a$4 >% .4 C
o=
y O 0 W .O
7 t0 E 6C 'O
-+ O O W O O
jj
H C N tJ N
CJ M v1 C
••C +
+ •0+ d E O+ u
r L 7 0 eD
aJ N . 4 Y.1
M L 7 O L
a•r u"� y
W V h
0 m 0 C 0
3 Lo 0 u F
.••� N P1 S
L/1
k7
0
Z
a
O
r�
W
y
u
V1
t
U
,
Q
ea
C
z
<
w
a
U
H
a
ir+
H
I
w
i
'i
I
r1
U
EA
Where Q a Average daily flow into the system.
(Gal /Day) See Table IV
Evaporation data for various sections of-the State is listed
in Table VI. Additional data may be found in "Report 192."
published by the Texas Department of Water Resources.
(D) Plants and Grasses'for Transpiration - The bed surface should
be: covered with perennial grasses to take advantage of
transpiration. Also, evergreen bushes can be planted in
the bed to assist in water uptake. If grasses are used
which have dormant periods, steps should be taken to provide
- some type of vegetation on the beds during these periods.
Overseeding with winter grasses is commonly used to provide
year -round transpiration.
(E) Geographical Location of Installation Considering Rainfall
Data :- Some areas•of the State with high annual rainfall are
not well suited for the installation of evapotranspiration
systems. Counties in the eastern part of the State in which
the annual rainfall exceeds the annual evapotranspiration
should only utilize this type of system as a last resort and
with extreme caution. For the system to be expected to perform
in the desired manner, the evapotranspiration beds must be
mounded and compacted to exclude as much rainfall as possible.
Also, shrubs, bushes and trees with broad rain deflecting
leaves should be planted over the beds and good drainage
away from the beds must be provided, and in some areas
_ where high water tables exist the beds should be lined to
exclude ground water.
(g) Percolation Test Procedures
(1) Location and Number of Tests
(A) A minimum of two test holes will be required with the holes
uniformly spaced over the proposed absorption field site.
The actual number of holes required for an individual soil
evaluation should be determined experimentally in accordance
with the following procedures:
(B) If the percolation rate results of both test holes both fall
in the same group as shown in Column One in Table V, no
additional holes will be necessary and the absorption field
may be designed on the average of the results.
-30-
C
TABLE VI
MEAN PAN EVAPORATION IN TEXAS
Station
Amarillo
Austin
Beaumont
Brownsville
Canyon Lake
Daingerfield
Dallas
E1 Paso
Fort Stockton
Houston
Lake Sommerville
Lubbock
Temple
-31-
Ea
MAM
Evavoration Rate
(Inches/YwJ
67.9
78.8
47.8
56.0
80.8
74.2
85.0
106.5
105.6
48.7
71.7
88.7
68.2
C.
•
(C) If.tbe percolation rate results fall in adjacent groups,
the absorption field may be designed using the test results
from`tbo hole with the lowest percolation rate or one
additional hole may be dug, tested and all three results "
averaged.
(D) If the percolation rate results fall in non - adjacent
groups, the absorption field may be designed using the
test results from the hole with the lowest percolation
rate or =two additional holes may be dug, tested and all
results averaged.
(E) In lieu of the above procedure, four holes may be dug and
tested and the results averaged at the same time to reduce
the amount of time required to,condnct the test.
(2) Type of Test Role - Dig or bore a hole with horizontal dimensions
of from 12 to 15 inches and vertical sides to the depth of the
prop.osed.absorption trench. Smaller diameter holes will not
yield accurate results.
(3) Preparation of Test Holes - Carefully scratch the bottom and sides
of the hole with a knife blade or sharp- pointed instrument in
order to'remove any smeared soil surfaces and to provide a natural
soil interface into which water may percolate.. Remove all loose
material from the hole and carefully place approximately one inch
of coarse sand or gravel in the bottom of the hole to protect the
bottom from scouring.
(4) Saturation and Swelling of the Soil - It is important to distinguish
between saturation and swelling. Saturation means that the void
spaces between soil particles are full of water. This can be
accomplished'in a short period of time. Swelling is caused by
intrusion of water into the individual soil particle. This is a
slow process, especially in clay -type soil, and is the reason for
requiring a prolonged soaking period.
(5) Filling of Test Holes - In the conduct of the test, carefully fill
the hole`with' clear water to a minimum depth of 12 inches. In
most soils, it is necessary to refill the hole by supplying a
surplus reservoir of water manually or by means of an automatic
siphon, to "keep water in the hole until saturation occurs
(approximately 24 hours). Determine the percolation rate 24
hours after water is first added to the hole. This procedure is
to insure that the soil is given ample opportunity to swell and to
approach the condition it will be in during the wettest season
of the year. Thus, the test will give comparable results in the
same soil, whether made in a dry or in a wet season. In sandy
soils containing little or no clay, the swelling procedure is not
essential, and the test may be made as described under Rule .002(8)(7)
after the water from one filling of the hole has completely seeped
away.
-32-
C7
n
bv
(6) Percolation Rate Measurement - With the exception of sandy soils,
percolation rate measurements shall be made on the day following
the procedure described under Rule .002(g)(5) above. If water
remains.in the test hole after the overnight swelling period,
adjust the depth to approximately 12 inches from the bottom.
From a fixed reference point, measure the drop in water level
over a °30 minute period. This drop is used to calculate the
Percolation rate. If no water remains in the hole after the
overnight swelling period, add clear water to bring the, depth of
waterier the hole to approximately 12 inches from the bottom,
wait 30 minutes, refill the hole to a 12 inch depth and measure
theArop in water level over an additional 30 minute interval
to '' determine the percolation rate.
(7) Percolation Rate Measurement (Sandy Soils) - In sandy soils (or
other soils in which the first 6 inches . of water seeps away in
less than 30 minutes, after the overnight swelling period),
the bole should be filled to a depth of 6 inches and that depth
maintained by adding water for 30 minutes. After 30 minutes, the
dropin; water level should be measured over an additional 10
minute period and the percolation rate Calculated from this
measurement.
(h)' Septic Tank Maintenance
(1) A septic tank system should not be treated as if it were a city
sever.- Economy in the use of water helps prevent overloading of
a septic tank system that could shorten its life and necessitate
expensive repairs. Leaky faucets and running commodes should be
carefully guarded against, and relatively little indigestible
waste or garbage should be placed in a septic tank system. Use
i! of a garbage grinder can cause a rapid buildup of sludge or scum,
which means more frequent cleaning and possible system failure.
(2) A septic tank system can serve a home satisfactorily only if
it is properly designed, installed and adequately maintained.
When a septic tank system is improperly designed or maintained,
liquid wastes may overflow onto the ground surface or the plumbing
in the home may become stopped up. These overflows not only
create offensive odors, but are also a health hazard. Sewage
may contain dysentery. infectious hepatitis, typhoid and paratyphoid
or other infectious disease organisms. Ponded sewage creates
breeding places for mosquitoes and some other insects.
(3) The purpose of a septic tank is to condition household wastes,
including body waste, discarded food scraps and in some cases
laundry and bath wastes so that it may be more readily percolated
into the subsoil. The normal use of bleaches, detergents, soaps
and drain cleaners does not harm or interfere with the operation
of the system.
-33-
LJ
L`
w'rrakr
f f
(4) The partially treated sewage effluent flowing from the tank still
contains large numbers of harmful bacteria and organic matter in
a finely divided state or.in solution. Foul odors, unsightly
conditions: and health hazards will develop if this effluent is
ponded .,on::,tie surface of the ground or carried away in open
ditches. inal disposal of the effluent in a subsurface soil
absorption' system is necessary to avoid these problems.
(i)
(S) The bacteria present in a septic tank are able to thrive in the absence
of oxygen. Such decomposition in the absence of air is- called
"septic, "'.which led to the naming of the tank. Solids and scum
are digested and reduced to a smaller volume by the bacteria in
the tank. However, a residue of inert solid material remains
which must be stored during the interval between tank cleanings.
(6) The frequency of cleaning depends on the size of the septic tank
and the number of people it serves. When a garbage grinder is
used, more frequent cleaning will be required. With ordinary
use and care, a septic tank may require cleaning every two or
three years.. In many cases, septic tanks can be satisfactorily
operated.even longer. The homeowner can make measurements and
decide for himself when his tank needs cleaning. An annual check
is the best procedure. When the bottom of the scum is within
three inches of the bottom of the outlet tee, the tank should
be cleaned; The accumulated solids are ordinarily pumped out
by commercial septic tank cleaner companies. The solids removed
should be disposed of in a manner approved by the Texas Department
of Health to avoid obnoxious odors and health hazards.
4n -Site Aerobic Sewage Treatment Plants For Individual Residences - In
recent years;`a number of home aerobic wastewater disposal systems have
been designed and marketed for the on -site treatment of sewage. The
following information is a joint Texas Department of Water Resources -
Texas Department of Health statement concerning the installation and
use of on -site sewage treatment plants for individual dwellings.
(1) The installation and use of individual wastewater disposal
units other than septic systems is not opposed by the Texas
Department of Health or the Texas Department of Water
Resources.
(2) Subject to the requirements of the local government or local
health department, and with their permission, a home owner may
select to use an aerobic individual home wastewater disposal
system.
(3) The effluent from an individual home aerobic wastewater disposal
unit must be discharged into a properly designed and constructed
soil absorption or evapotranspiration system. No discharges to
the ground surface or into the waters of the State are authorized.
-34-
LF, l
:7
(4) As a.practical matter, companies distributing aerobic individual
home waste disposal systems should provide an inspection and
repair service since the homeowner, in most instances, will not
be it a position to judge whether the device is working as
designed. Local governments, in determining whether to approve
any:type of individual home waste disposal system, may wish to
give "consideration to the ability of the distributor.to service
the installation.
(5) The principle structure or containing vessel of an individual
home wastewater disposal unit should be designed to provide
treatment to incoming sewage in the event of failure of
mechanical and electrical devices. Since anaerobic conditions
will' ::prevail when aeration equipment is inoperable, the unit
should be designed to function in a septic- tank -like manner
during periods when the aerating device is not functioning.
(6) There are numerous manufacturers of individual home wastewater
treatment systems. To the extent of available information,
inquiries on individual systems from local governments or
individuals will be answered by the Texas Department of Health.
Local governments interested in authorizing individual home
aerobic wastewater disposal systems are advised of the testing
and approval program of the National Sanitation Foundation.
The N.S.F. seal on a particular unit indicates its ability to
meet the requirements of the Foundation's Standard 40 relating
to "Individual Aerobic Wastewater Treatment Plants."
.003. Common Unsatisfactory On -Site Disposal Systems - The construction and
use of these systems constitutes a violation of the Texas Sanitation
and hearth Prot-ection raw, Article 4499 -1, v.T. -C.S.,-Sections 23fb),
24 and 25. The Department considers the following on -site sewage
disposal systems unsatisfactory because they tend to create nuisances
and other conditions prejudicial to the public health:
(a) Cesspools - Cesspools were once commonly used in rural areas for
disposal of domestic wastes. Cesspool design consisted of construct -
ing a pit into permeable soil and curbing the sides of the pit with
open jointed material to the bottom of the pit. Raw sewage was
discharged directly into the cesspool and the organic material
anaerobically decomposed while the partially treated wastewater was
absorbed by the adjacent permeable soil. Since the threat of injury
to public health is greater When raw or partially treated wastewater
is in direct contact with the absorptive soil, this method can no
longer be considered as an approved means of sewage disposal.
-35-
r1
�J
n
u
(b) Bore Holes and Injection Wells
(1) Bose holes and injection wells used for disposal of domestic
wastes generally consist of a drilled hole greater than'4
feet in,deptb'and varying in diameter from 8 inches to 36
inches or larger. Usually, the holes are filled with crushed
stone and are dug to a depth which intercepts a permeable
soil layer. Raw sewage is discharged into these holes directly
or after detention in a septic tank.
(2) The use of bore holes or injection wells for domestic sewage
disposal is not an approved disposal method because of the
possibility of contamination of underground water. Injection
wells approved and permitted by the Texas Department of Water
Resources are acceptable to the Texas Department of Health.
Injection wells used for private sewage disposal as defined in
Rule 002(a)(12) are not subject to regulation by the Texas
Department of Water Resources or the Federal Safe Drinking
Water Act, however, their use will not generally be subject
to approval by the Texas Department of Health. Variations of
bore hole design such as soil substitution methods may be
approved as stated in Rule .002(b)(2) of these standards.
(c) Seepage Pits
(1) Seepage pits are rock - filled or lined pits dug to a depth in
excess of 4 feet and located at the end of a septic tank
absorption field system. The pits are generally used to
dispose of wastewater which would normally not be absorbed
in the absorption field and would otherwise surface.
(2) Seepage pits are not an approved method of wastewater disposal
for the same reasons that apply° to bore holes and injection
wells. Subsurface water contamination may occur with these
systems and the anaerobic bacteria present in the wastewater
may eventually cause plugging problems in the seepage pit.
-36-
rI
v