Frequently Asked Questions About Septic Aerators (Air Pumps)

Septic air pumps, commonly called aerators, are critical components in aerobic septic systems and also widely used for pond aeration. Below is a clear, straightforward guide covering how they work, common problems, maintenance tips, and other key details.

What does a septic air pump do? It forces air (oxygen) into the treatment tank of an aerobic septic system or into a pond. The extra oxygen feeds aerobic bacteria that break down waste much more effectively than anaerobic bacteria do. In ponds, the same process keeps water oxygenated for fish and helps control algae.

Why has my septic air pump stopped running? The most frequent causes are:

• Dirty or clogged air filter – restricts airflow and strains the pump.
• Worn-out diaphragms (in linear diaphragm pumps like Hiblow or FujiMAC) or vanes (in rotary vane models) – usually after 3–6 years of use.
• Electrical problems – tripped breaker, bad wiring, or no power reaching the pump.
• Blockages in the airline or diffuser – forces the pump to work harder and can eventually cause failure.

How often should I service my aerator?

• Clean the air filter every 6 months; replace it once a year.
• Inspect/replace diaphragms or vanes every 3–5 years (or when performance drops).
• Listen for odd noises or check the alarm every couple of months.
• Schedule a professional service every 2–3 years for a thorough check and cleaning.

How long do these pumps typically last? A good-quality linear diaphragm pump (e.g., Hiblow HP series) can run many years with regular maintenance. Using genuine rebuild kits to replace diaphragms, filters, and other wear parts can increase the lifespan.

Can an aerobic septic system work without the air pump? No. Without constant aeration, the beneficial aerobic bacteria die off, waste isn’t properly treated, and the system essentially turns into raw sewage. Anaerobic (conventional) systems don’t need an aerator, but aerobic ones absolutely do.

How do I choose the right size pump? Sizing is based on your system’s daily flow (gallons per day) and the required airflow (liters per minute) plus pressure. Typical matches:

• 500–600 GPD systems → 60-80 LPM pump (e.g., Hiblow HP-80)
• 650-850 GPD systems → 100-120 LPM models (HP-100LL, HP-120LL, etc.)
• 1,000-1,100 GPD systems → 150 LPM models (HP-150) 
• 1,350-1,500 GPD systems → 200 LPM models (HP-200)
• Always confirm exact airflow and pressure requirements with your septic system manual or a licensed installer.

Why is the septic alarm sounding?

Usually one of two things:

1. The aerator has failed or is delivering very little air (bad diaphragm, clogged filter, power issue).
2. Water level in the tank is too high (clogged outlet, failed sprinkler/chlorine pump, stuck float, etc.). Start by checking/cleaning the filter and verifying the pump is actually running and pushing air.

How can I tell if the pump is delivering enough air?

• Disconnect the airline at the tank and feel for strong, steady airflow.
• Look at the treated effluent – if it’s smelly or cloudy, aeration is probably insufficient.
• Compare actual airflow against the manufacturer’s performance curve, or have a tech measure it with a flow meter.

Is it okay to install the pump myself?

Many homeowners do it successfully. Key points:

• Use the correct hose diameter to avoid excessive backpressure.
• Mount it in a shaded, well-ventilated spot (or inside a protective enclosure).
• Follow the wiring diagram exactly. If you’re not comfortable with electrical work or local codes are strict, hire a professional.

How much electricity do they use? Very little. Examples (running 24/7):

• HP-80 ≈ 71 W → ~$9–14/month
• HP-120 ≈ 120 W → ~$15–25/month (Actual cost depends on your local kWh rate.)

Are septic air pumps loud? Quality linear pumps run at 35–45 dBA – about the level of a quiet refrigerator. Placing them on a solid base and inside a vented cover keeps noise minimal.

What if the pump gets flooded? 

Most septic air pumps are UL-rated for outdoor use but are not waterproof. If the pump gets wet:

• Disconnect power immediately to avoid electrical hazards.

• Remove the pump from water and dry it thoroughly.

• Inspect for damage, especially to electrical components and diaphragms.

• Do not restart until fully dry and inspected by a professional, as water damage may require repairs or replacement.

Should I use generic/aftermarket rebuild kits?

Generally not recommended. Off-brand parts often don’t meet the exact tolerances and can shorten pump life or void any remaining warranty. Stick with OEM (original manufacturer) kits for reliability.

For any issues you can’t resolve yourself, contact a licensed septic technician or the pump manufacturer directly – they can guide you through diagnostics or arrange service.