Basic Septic System Rules for Oklahoma

Division of Agricultural Sciences and Natural Resources • Oklahoma State University

PSS-2918

Oklahoma Cooperative Extension Fact Sheets

are also available on our website at:

http://facts.okstate.edu

Oklahoma Cooperative Extension Service

October 2017

Sergio M. Abit Jr., PhD

State Specialist for On-site Wastewater Treatment Systems

Emily Hollarn

Environmental Specialist

Oklahoma Department of Environmental Quality

Many of us want to build or buy houses in the country, for

a variety of reasons. Living outside of city limits allows for the

opportunity to be closer to nature, the ability to grow vegetables

and raise farm animals and the chance to live a simple and

relaxed life in a rural setting. One thing to bear in mind is, that

while living in the country has tremendous beneﬁts, access to

the conveniences that towns provide are not always available.

For instance, a country home would most likely be outside the

service area of the city water and sewer system – meaning

the need for your own safe and reliable source of water and

the need to treat household wastewater within the property.

For the latter, an on-site wastewater treatment system, most

commonly known as a septic system, is needed.

There are three key things to remember with septic sys-

tems: 1) they are expensive to install, 2) they need care and

maintenance and 3) there are rules that govern their instal-

lation and maintenance. This fact sheet articulates the rules

you need to know regarding securing an installation permit,

site and soil restrictions, and installation and maintenance of

septic systems. For additional details about maintenance of

septic systems and the various types of systems permitted

in Oklahoma, refer to Extension fact sheets PSS-2914, Keep

Your Septic System in Working Order and PSS-2913, On-site

Wastewater Treatment Systems Permitted in Oklahoma.

In Oklahoma, rules that pertain to septic systems are

conveyed in Title 252 of the Oklahoma Administrative Code

Chapter 641, “Individual and Small Public On-Site Treatment

Systems.” This Code was used as reference in preparing this

fact sheet. While much of this fact sheet is written in a simpli-

ﬁed question-and-answer format, there are parts that are lifted

almost verbatim from the Code.

Site Requirements and Restrictions

Is there a minimum home lot size requirement?

If public water (water from city or rural water district) is

used, the minimum lot size requirement for a house needing

a septic system is ½ acre for most systems. If an individual

drinking water well is used, then a minimum lot size of ¾ acre

is required for most systems.

Basic Septic System Rules

for Oklahoma

What is a “repair area” requirement?

Aside from the area allocated for septic system installa-

tion, enough area should be designated as repair area. This

is the area where dispersal lines of the septic system will be

installed in case the ﬁrst system installed fails.

When buying a house, ask where the designated repair

area is located. Make sure the repair area is big enough for

system installation and no permanent structures are built on

the area.

Where can the septic system be installed?

All components of the septic system, including tanks,

pumps, dispersal ﬁelds and collection line(s) need to be

installed within the property of the owner of the system and/

or in a dedicated recorded easement for the installation and

operation of the septic system. Keep in mind there are sepa-

ration distances from objects such as water wells, property

lines, buildings as well as other rules.

What is a ‘Water Body Protection Area’ and is the

property is in it?

Water Body Protection Areas (WBPA) are those areas

located within at least 1,320 feet from water bodies (e.g. rivers

and lakes) designated by the State to be specially protected

from pollution. Areas in the WBPA, speciﬁcally those within

660 feet from a listed water body or scenic river corridor re-

quire advanced systems with a nitrate-reduction component.

This means the septic system for that area will cost more. To

determine whether the property is within the WBPA, check with

the local DEQ ofﬁce or go to http://gis.deq.ok.gov/ﬂexviewer/.

It should be noted that the requirement for a nitrate-reduction

component applies only to new houses or modiﬁcation on a

septic system of an existing house.

How much land area is required for the septic

system?

While not stipulated as a rule, it is suggested that at least

10,000 square feet be allocated for the septic system in the

area where it will be installed. In addition, the area should

be accessible to the installer and the equipment needed in

earth-working activities related to the installation.

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The actual size of the area required for the septic system

will initially depend on soil and site properties in the area. Soil

properties and site location (relative to protected water bodies)

will dictate what type of septic systems may be permitted for

the site. Once the appropriate septic system is determined,

the number of bedrooms in the house is then taken into con-

sideration to determine the actual size of the area that must

be allocated for the septic system. The same determines the

size of the designated repair area.

As a rule of thumb, the ﬁner the soil texture in the area

(more clay in the soil), and the more bedrooms in the house,

the wider the area needed for the septic system.

Required Soil Evaluation

As mentioned earlier, soil and site properties determine

the type of septic system permitted for installation, as well as

size of the land area that is needed. Tests must be performed

to determine soil properties.

What soil test needs to be performed?

There are two soil tests: 1) Soil Proﬁle Description and

2) Percolation Test. Results of a percolation test serve as an

indicator of the rate of subsurface water ﬂow at depths where

household wastewater is normally applied. The soil proﬁle

description mainly involves the determination of soil texture

(how ﬁne or coarse is the soil) and soil color at 6-inch depth

intervals from the surface down to 48 inches or until a ﬂow-

restricting layer is found.

Either test could serve as basis in making septic system-

related decisions. But in sites located within the WBPA, a soil

proﬁle description is mandatory. It should also be noted that the

land area required for the septic system is generally smaller

if the test performed is a soil proﬁle description. It is always

best to start any septic system decision-related process with

a soil test. However, if the decision has already been made to

install a lagoon system or an aerobic treatment system with

spray irrigation, then a soil test is no longer required.

Who can perform soil tests?

Only State-certiﬁed soil proﬁlers can perform soil proﬁle

descriptions. A list of soil proﬁlers can be found at http://www.

deq.state.ok.us/eclsnew/OnSite/soilproﬁlers.htm. Environ-

ment Specialists at the Department of Environmental Quality

(DEQ) can also perform soil proﬁle descriptions. Percolation

tests can be performed by professional engineers, licensed

sanitarians, environmental specialists or soil scientists. Results

from these tests are used by installers to design the septic

system that would be submitted to the DEQ for approval.

Note: There are municipalities in Oklahoma requiring a soil

test report before issuing a building permit.

Permits

What needs a permit?

All new installations of septic systems in a property, in-

cluding the installation of an additional system, need to have

a permit before it can proceed. Modiﬁcations of an existing

system also need a permit. Septic system modiﬁcations may

be needed as a result of the following: a) malfunctioning

septic systems, b) home renovation leading to an increase

in the number of bedrooms, c) increase in water use due to

change in use of a house or building and d) relocation of any

component of a septic system. A permit must be secured

before work can start.

Where and how to get an installation or modiﬁca-

tion permit?

The DEQ is the permitting and regulatory agency for

requests and issues related to on-site septic systems. To ap-

ply for a permit, simply go online at https://applications.deq.

ok.gov/sewagepermit/ or contact your local DEQ ofﬁce for

assistance. Contact information and locations of your nearest

local DEQ ofﬁce could be found at http://www.deq.state.ok.us/

eclsnew/localOfﬁces.htm. Often, the installer will process the

installation or modiﬁcation permit application for you.

Inspections

Who conducts inspections and when are they

necessary?

There are two cases where an inspection by a DEQ

personnel is necessary. They are: 1) repairs and system

modiﬁcations performed by a non-certiﬁed installer and 2)

installation of new systems by a non-certiﬁed installer. The

inspection must be performed before the installation, modi-

ﬁcation or repairs are backﬁlled and/or before the system is

placed into operation.

It should be noted that if the installation, modiﬁcation or

repair is performed by a state-certiﬁed installer, there is no

need for a DEQ personnel to perform an inspection because

certiﬁed installers are allowed to perform self-inspection.

Who is responsible for arranging a DEQ inspec-

tion?

The installer shall be responsible for requesting any re-

quired DEQ inspection related to an installation, modiﬁcation

or repair. Inspections related to complaints will be managed

by the DEQ personnel.

Installation

Who can install a septic system?

It is recommended that you utilize the services of a state-

certiﬁed septic system installer. A list of state-certiﬁed install-

ers can be found at http://www.deq.state.ok.us/ECLSNew/

CertInstallers/certInstallers.htm or from the local DEQ ofﬁce.

The State of Oklahoma allows non-certiﬁed installers to

install a limited number of systems. However, these instal-

lations must be inspected and approved by DEQ personnel

before they are backﬁlled and/or made operational.

Are new installations covered by a mandatory

warranty/maintenance period?

Installers are free to offer their own version of a warranty/

maintenance package to their clients for a fee. However, if the

system installed is an aerobic treatment system/unit (ATU),

Oklahoma rules require a two-year warranty. This rule man-

dates the installer of an ATU to maintain the system at no

additional cost to the homeowner for two years following the

date of installation. Within this period, the installer is required

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to inform the owner of the operational status and any repairs

or replacements performed with the system.

If you buy a house and the ATU in the house is still within

the warranty period, you are eligible for the warranty until the

two-year period expires.

Responsibilities of the Owner

Properly working septic systems will treat harmful pol-

lutants in household water. Improperly-functioning systems

pose as hazards to the owners, their neighbors and the

environment.

The rule clearly stipulates that the owner of a system shall

ensure that the system is maintained and operated properly

so that: 1) sewage or efﬂuent from the system is properly

treated and does not surface, pool, ﬂow across the ground

or worse, discharge to surface waters, 2) all components of

the system including lagoons are maintained and do not leak

or overﬂow and 3) the required security measures are intact

(e.g. required fences are intact, septic tank lids are intact and

properly secured).

The rules also state that if a septic system malfunctions,

the person owning or otherwise responsible for the system

needs to take prompt action to repair the malfunctioning system,

prevent further violations and remediate the site. Violations and

negligence are subject to enforcement actions and possible

penalties.

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