Aerobic Treatment Maintenance

Aerobic System

Know Your Aerobic Treatment System

Aerobic systems are on-site, multiple-stage wastewater treatment systems that use forced aeration to promote bacterial growth in order to break down organic matter and prepare the treated water for dispersal. Aerobic systems are typically composed of 4 chambers which may be housed as one unit or installed as separate units (as shown below).

Aerobic System Image

1. The first stage of treatment, the Trash Tank, separates the solids from the liquid wastewater.

2. The Aerobic Treatment Unit (ATU) forces compressed air bubbles through the wastewater creating a highly oxygenated (aerobic) environment for bacteria to break down the organic matter and further clarify the water.

3. The wastewater is then disinfected in the Disinfection Chamber making the water suitable for surface dispersal.

4. The Pump Tank transports the treated effluent to either a Surface Sprinkler Irrigation System or a Drip Irrigation Field

Homeowner Responsibilities

On-site wastewater treatment systems are an effective means to treat wastewater. However, it’s important to note that these systems can result in surface and/or groundwater contamination for a variety of reasons, such as improper location of the system, poor design, faulty construction, incorrect operation, and poor maintenance. 

Aerobic Alarm Requirement

Correct operation and maintenance includes: checking chlorine residual monthly, contacting a septic specialist immediately if alarm activates, practicing water conservation techniques, maintaining inspection records, monitoring sludge build-up in the chambers, maintaining landscaping near irrigation system, inspecting sprinkler heads for clogs, and using septic-safe detergents and toilet paper.  It is also advisable to avoid pouring chemicals and cleansers down the drain that may harm the beneficial bacteria in the ATU. By keeping your on-site system in good working condition, you will save money, increase the value of your home, and protect the environment.  


  • May be used to correct failing septic systems
  • Produces consistently high-quality effluent
  • May be installed in a wide variety of soil types
  • Required installation space is minimal allowing for placement flexibility
  • Treated wastewater may be used for irrigation, allowing for water reuse


  • More expensive to install, maintain, and operate than traditional septic systems
  • Requires more inspection and monitoring than other systems
  • Untreated water can be introduced into the environment if a portion of the system fails
  • Spray irrigation can potentially drift downwind and encroach on other properties
  • Long power outages pose a problem since electricity is required for the system to operate
State and Local Requirements

State Requirements

For an aerobic system to be installed in Oklahoma, an installer is required to submit 3 different forms to The Oklahoma Department of Environmental Quality (ODEQ): Forms 641-581SP, 641-581Cert, and 641-575. ODEQ also requires that all aerobic system installers provide a 2-year service and maintenance agreement to the homeowner that includes at least 4 inspection/service visits (ODEQ Title 252.641.10). In-between service visits, ODEQ recommends that homeowners check the level of chlorine in their system and add additional chlorine as necessary. At the end of the 2-year contract, the maintenance responsibility falls to the homeowner unless the contract is renewed.

Local Requirements

The City of Edmond requires all builders of new residential properties with aerobic systems to provide a 2-year maintenance agreement in accordance with City Ordinance No. 3477, specifically 21.03.091 Section 3. After 2 years, the homeowner will be responsible for providing yearly verification of continued professional inspections and maintenance to the City of Edmond.

For additional information, please visit EPA's webpage regarding Aerobic Treatment Systems.