Updated October 2026. Checked against U.S. EPA and Texas TCEQ guidance and manufacturer specifications.
The air pump (aerator) on an aerobic septic system blows air into the treatment tank so oxygen-loving bacteria can break down the waste. When it fails, treatment stops and the tank turns smelly fast. The right replacement is the model your treatment unit maker specifies, or one with the same airflow (liters per minute) and pressure rating, not simply the biggest pump. Most home systems use linear diaphragm pumps such as the Hiblow HP-80 or HP-120.
Signs your septic aerator is not working
- The alarm on the control panel is on, or the panel shows a low air pressure warning
- The air pump is silent, or it hums but you feel no air at the outlet
- No bubbling in the aeration chamber when the lid is opened by your service provider
- A strong sewage or rotten egg smell from the tank or spray area
- Cloudy or smelly water coming out of the spray heads
Before replacing the pump, check the breaker and any GFCI outlet it plugs into. A tripped circuit is a common and cheap fix. Do not open the tank yourself; aerobic tanks hold gases and are a fall hazard. See how to reset a septic tank alarm.
Aerator down or alarm going off?
An aerobic system without air stops treating wastewater. Talk to a local septic company about a repair or replacement pump.
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Types of septic aerators
| Type | Where it sits | Notes |
|---|---|---|
| Linear diaphragm air pump | Outside, in a small box or on a pad | Most common on newer home systems. Quiet; diaphragm kits can be replaced instead of the whole pump |
| Rotary vane compressor | Outside, near the tank | Used on some older and larger units; louder |
| Jet or submerged aerator | Mounted on the tank, motor above the water | Built into certain brands; replaced with that maker part |
The EPA describes aerobic treatment units as systems that inject oxygen into the treatment tank and notes that regular maintenance should be expected for the life of the system. For how the aerator fits in, see what a septic aerator does and how an aerobic septic system works.
How to choose a replacement septic air pump
- Start with the data plate. Your treatment unit or the old pump lists the model, airflow and pressure. Matching it is the safest choice.
- Match airflow. Home pumps are usually rated in liters per minute (LPM). Hiblow sells the HP-80 at 80 LPM and the HP-120 at 120 LPM; your treatment unit maker sets which size the tank needs.
- Match pressure. The pump has to push air down to the diffusers. Premier Tech lists the Hiblow HP-120 at a rated pressure of 17.7 kPa.
- Look for alarm and back-pressure protection. Some pumps include a low-pressure alarm or a safety valve that protects the pump if a diffuser line clogs.
- Check your service contract. In Texas and other states with required maintenance contracts, ask your provider which replacements are approved for your unit.
Power use adds up because the pump runs around the clock. Premier Tech lists the HP-120 at 120 watts; running nonstop, that is about 86 kWh a month. See how much electricity an aerobic system uses.
Popular septic aerator air pumps
| Pump | Airflow (maker or seller) | Good for | Shop |
|---|---|---|---|
| Hiblow HP-80 | 80 LPM | Smaller home units that call for an 80 LPM pump | Check price on Amazon |
| Hiblow HP-120 (and HP-120LL) | 120 LPM; 120 W | Larger home units that call for 120 LPM | Check price on Amazon |
| ET100A septic air pump | Seller lists it with a low-pressure alarm and back-pressure safety valve | Owners who want a built-in alarm | Check price on Amazon |
| Hiblow diaphragm rebuild kit | Not a pump; restores airflow on a worn Hiblow | Pumps that run but push less air | Check price on Amazon |
As an Amazon Associate we earn from qualifying purchases. Claims come from each maker or its Amazon listing; we have not lab-tested these products.
If you need a pump for a different job, such as moving effluent to a drainfield or spray field, see septic effluent and sewage pumps.
Quick answers
How long does a septic aerator last?
The EPA says pumps and controls on septic systems usually last 10 to 20 years. Diaphragm pumps often need a diaphragm kit sooner, so ask your provider to check airflow at each visit.
Can I turn off my septic aerator to save power?
No. Without air the bacteria die off, treatment stops and the system starts to smell. Many control panels will also sound an alarm.
Why is my aerator making a loud noise?
A rattling or louder hum often means worn diaphragms, a loose mount or a clogged air line. Have it checked before it fails.
Who should replace a septic air pump?
It depends on your state and permit. In Texas, most aerobic systems have a maintenance provider, who should handle or approve replacements.
Sources
- U.S. EPA, Types of septic systems
- U.S. EPA, Why maintain your septic system
- Premier Tech Aqua, Hiblow HP-120 specifications
- Texas Commission on Environmental Quality, FYI on OSSFs