Oklahoma aerobic septic rules: maintenance, chlorine and spray
Aerobic systems with sprinklers are common around Edmond, Norman, Yukon and Mustang because they work in heavy clay. They also come with the most rules. This page sums up what Oklahoma DEQ requires. For day-to-day care, see our aerobic system care guide and alarm help. Checked November 2, 2026.
The two-year installer maintenance period
Whoever installs an aerobic system must maintain it for two years from installation at no extra cost to the owner (OAC 252:641-10-3, DEQ aerobic systems fact sheet). During those two years the installer must, at least every six months:
- repair, adjust or replace broken parts;
- test and record the free chlorine in the pump tank when spray is used;
- measure sludge in the trash tank and the aerobic unit;
- run a clarity test in the pump tank (an 8-inch black and white disk must be visible on the bottom when the tank is at least one-third full);
- tell the owner in writing what was done, and keep records for three years.
Sludge should never fill more than 40 percent of the trash tank depth or aerobic unit volume. The installer is not responsible for damage the owner alone caused, like mowing over sprinkler heads or flushing harmful items (DEQ fact sheet). If your installer skips the required visits, DEQ asks you to call 1-800-522-0206.
After two years
The owner becomes solely responsible for maintaining the system or hiring someone to do it (OAC 252:641-10-3). The state rule does not force a paid contract after year two, but your city may. Edmond, for example, runs its own aerobic maintenance program (City of Edmond aerobic treatment maintenance).
Chlorine
Spray systems must disinfect the water. If chlorine is used, the pump tank must hold a free chlorine residual of at least 0.2 mg/l (OAC 252:641-10). Use tablets made for wastewater chlorinators, not pool tablets, unless the maker approves them.
Spray field rules
- At least two sprinkler heads, and a vegetated or terraced field so water does not run off.
- Spray stays low, at a trajectory of no more than 15 degrees, without misting.
- A timer runs the spray daily between 1:00 a.m. and 6:00 a.m.
Source: OAC 252:641-12-7 (DEQ rules, OAC 252:641).
Need help?
Find a certified installer on the DEQ list of active certified installers, check fees on our permit and fee page, or ask local companies for maintenance quotes.
Related: permit steps and fees · inspection when buying · aerobic rules · signs of failure · all septic rules