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Aerobic System Fact Sheet

Aerobic System Manual

Listing of Certified Installers



Aerobic treatment systems are on-site sewage treatment systems that use forced air to treat wastewater and surface application or drip irrigation to disperse the treated wastewater. These types of systems are much more complex than others and require more maintenance.

There are several different brand names of aerobic systems, but they all operate the same basic way. Air is forced into a tank promoting an aerobic environment. Once the aerobic organisms digest and treat the wastewater, the water is either disinfected and sprayed on the ground surface or distributed into drip irrigation tubing below the ground surface.

Responsibility of Maintenance

The installer of any aerobic treatment system is required to maintain the system for two years following the date the system was installed at no additional cost to the owner. During the two-year mandatory maintenance period, the installer is responsible for the following:

  • repairing, adjusting or replacing any broken or malfunctioning parts unless the homeowner is the sole cause of the damage to the system (e.g. sprinkler heads damaged by homewoner, excessive water usage, intorduction of harmful items into septic system)

  • 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 the aerobic treatment unit at least once every six months

  • conducting a clarity test and recording the results as passing or failing once every six months

  • notifying the owner of the system in writing of the type and date of any repairs, results of the free chlorine residual and clarity test, when to add chlorine and how to do it, when to have the trash tank and the aerobic treatment unit pumped so that the depth of sludge is never more than forty percent of the overall depth

  • 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

After the expiration of the two-year mandatory 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.

Follow the steps below to insure your aerboic system is operating effectively and efficiently:

1. Review the owner's manual (if you do not have an owner's manual, contact the individual that installed the system).

2. Listen. You should be able to hear the compressor running. This is the equipment that forces air into the unit.

3. Smell. Foul odors (like rotten eggs) could be an indication that the system is not working properly.

4. Chlorine should always be in the system to ensure proper operation. Check chlorine levels often.

5. Although it is not required, it is recommended that homeowners enter into a maintenance agreement with an authorized representative for routine checks and repairs.


Water DropOn-site treatment systems are designed to treat and disperse a set number of gallons of wastewater a day. If the amount of wastewater is exceeded, then your on-site system may malfunction. It is recommended that water-conserving fixtures be installed in residences. Please contact your local DEQ office for additional information concerning maintenance of your on-site system.