Conventional septic systems rely on a tank and a soil treatment field. Aerobic systems add mechanical treatment so effluent can be sprayed or dripped where a conventional field is not practical.
Aerobic systems usually cost more to install and need electricity, disinfection, and more frequent attention.
If you are buying a home with an aerobic system, ask for maintenance records and whether the installer two-year window is still open.
Oklahoma soil, lot size, and local approval often decide which system is allowed. This site does not choose a system for you. It helps you find roster-matched companies after you know you have — or need — an aerobic spray system.
Repair and maintenance searches are different for the two system types. Ask any company whether it services aerobic systems before you book.
Which one does my lot allow
OAC 252:641-1-3 says the designer and installer shall comply with the minimum lot size requirements set forth in Appendix A, Figure 3. Plats recorded before January 1, 1974, are not subject to minimum lot size requirements, but systems installed in those platted areas must meet the construction requirements of the chapter. All minimum lot sizes listed in that figure shall exclude road easements and surface impoundments. The rule text points to the figure for the sizes. It does not print an acre number in the paragraph. Source: OAC 252:641-1-3.
OAC 252:641-10-1 states: “Aerobic treatment systems shall only be used for treatment of sewage and cannot be used when the average daily flow is less than one hundred (100) gallons per day or greater than one thousand five hundred (1,500) gallons per day or generates wastewater with a total Biochemical Oxygen Demand (BOD) greater than two and one half (2.5) pounds per day.” All other system designs must be permitted as alternative systems, as that section describes. Source: OAC 252:641-10-1.
Homeowners still ask for a perc test. OAC 252:641-3-2 says a percolation test may only be used to identify dispersal sites for conventional subsurface absorption fields. It is not the test for aerobic spray or drip. A soil profile is the description that identifies which dispersal fields the soil allows. OAC 252:641-3-4 uses that profile to size conventional subsurface fields, drip irrigation, and spray irrigation, among other field types. The person who writes a soil profile for a system design has to be certified by DEQ. DEQ may also perform the profile. A soil test is the usual step before a new system. OAC 252:641-3-1 lists two cases that do not require one: a lagoon, and an aerobic spray system sized for Group 5 soil in the matching net evaporation zone. Those exceptions are still not a perc test. A perc test stays limited to a conventional subsurface field. Source: OAC 252:641-3-1, 252:641-3-2, 252:641-3-4, and 252:641-22-1.
OAC 252:641-1-2 defines a conventional subsurface absorption field as a gravity-fed subsurface dispersal field that treats sewage in media-filled trenches. It may be preceded by a lift station. It is not an evapotranspiration field, and it is not a shallow extended field. Spray and drip are separate dispersal types. OAC 252:641-12-6 and 252:641-12-7 require both to be preceded by an aerobic treatment unit. How the rules define the treatment tank covers that tank apart from the yard. Soil-report steps for an Oklahoma City address walks through the same report choices for that city. This page does not list that city’s companies.
What each costs to keep running
This directory does not price jobs. The rules below say what has to be done. They do not state an installer price for that work.
OAC 252:641-10-2 says that if spray irrigation is used as the dispersal method, there shall be a method to disinfect the effluent. If chlorination is used, a free chlorine residual of two tenths of a milligram per liter (0.2 mg/l) must be maintained in the pump tank. When a pressurized dispersal method is used, there shall be a pump tank with a high-water alarm set to activate if the pump tank becomes more than one-half full. Source: OAC 252:641-10-2.
OAC 252:641-1-2 defines a conventional subsurface absorption field as a gravity-fed subsurface dispersal field. The maintenance duty in OAC 252:641-10-3 is for an aerobic treatment system, including one that provides nitrogen reduction. After the initial two-year period, that rule says the owner of the aerobic treatment system shall be solely responsible for maintaining or hiring someone to maintain the system so that it operates as designed.
DEQ fees, separate from upkeep
The figures below are Department of Environmental Quality fees for July 1, 2026 through June 30, 2027. They are not an installer’s price to build a system or to keep one running. A private soil profiler sets a separate price. This directory does not publish that price.
- Soil test, DEQ augered
- $357.28. DEQ augers the holes. This is a DEQ service fee.
- Soil test, applicant pits
- $214.36. The applicant provides the pits. Same fee schedule.
- Authorization, DEQ inspects
- $500.19. Authorization to construct when DEQ inspects and design flow is at or under 1,500 gallons a day.
- Authorization, self-inspect
- $357.28. Authorization to construct when the job is self-inspected, at the same flow limit. The fee schedule row is “Self Inspect.”
What the first two years include
OAC 252:641-10-3(a) states: “The installer of any aerobic treatment system including those providing nitrogen reduction shall maintain the aerobic treatment system for a period of two years following the date the system was installed at no additional cost to the owner.” During that period, the installer shall be responsible for the following, in the rule’s words:
- repairing, adjusting or replacing any broken or malfunctioning parts;
- when spray dispersal is used, testing and recording the free chlorine residual of the effluent in the pump tank at least once every six months;
- measuring and recording the depth of the sludge in the trash tank at least once every six months;
- measuring and recording the volume of the sludge in forced-air aerobic treatment units at least once every six months;
- when pump tanks are used, conducting a clarity test and recording the results as passing or failing once every six months. A passing clarity test is one where an eight-inch disk with alternating black and white quadrants is visible when placed on the bottom of the pump tank when the tank is at least one-third full;
- notifying the owner of the system in writing of all maintenance provided during each site visit;
- documenting all maintenance and testing performed on the system and maintaining those records at his/her business for a period of three years following the date of service.
OAC 252:641-10-3(b) states: “The installer shall not be responsible for repairing aerobic treatment systems when the owner/operator is the sole cause of the damage to the system or the system's malfunction (e.g., sprinkler heads that properly retract into the ground but are nevertheless damaged by careless actions of the homeowner, excessive water usage, introduction of harmful items into septic system, etc.).”
OAC 252:641-10-3(c) states: “After the expiration of the initial two-year maintenance period, the owner of the aerobic treatment system shall be solely responsible for maintaining or hiring someone to maintain the system so that it operates as designed.” If the installer does not provide the required maintenance, DEQ’s residential fact sheet says to call DEQ at 1-800-522-0206. Sources: OAC 252:641-10-3; DEQ, Residential Aerobic Treatment Systems. The treatment-tank guide covers the same two-year duty next to the tank itself.
Quick answers
Why do Oklahoma homes use aerobic systems?
Often because a conventional soil field is not practical on that lot. Confirm the reason with the installer or a local official.
Is an aerobic system set-and-forget?
No. It needs power, disinfection, and more frequent attention than a passive tank and field.
Use the directory as a starting point.
Ask the company to confirm your system type, exact task, property coverage, timing, and price. A directory record does not replace an on-site evaluation.
Start with aerobic septic installation, or companies that list a mailing city in Oklahoma City or Tulsa. Confirm coverage and ask for a written quote for your lot. This directory does not price jobs.