Many aerobic treatment units (ATUs) send treated effluent to a spray irrigation area. The pump that moves that liquid, and the spray lines and heads, are common places where a problem first shows up. This article describes the signs that may point to the pump or the spray line. It is for general understanding. It does not replace a professional inspection.
Signs that may point to the pump or spray line
- Sprinkler heads do not rise or spray when the pump should be running.
- Spray pattern is uneven, weak, or concentrated in one spot.
- Wet or soggy areas appear where no spray should reach, or the lawn stays dry where spray should land.
- The pump runs constantly, or does not run at all.
- The pump tank level is unusually high, or the high-water alarm sounds.
- The air compressor is quiet or silent, or there is a strong sewage odor.
Simple observations an owner can make
Oklahoma State University extension guidance suggests checking how the system responds during operation. Observe whether the sprinkler heads pop up and spray while the pump runs, and whether the coverage pattern looks normal. Note these observations, and the date and time, so you can describe them to the provider.
If the pump or alarm seems wrong, write down what the control panel shows and when it happens. Float switches and the pump tank are for the provider to test and adjust. Do not open the tank or change the float settings yourself.
Why a clogged or damaged line can matter
Spray heads and lines can become clogged or damaged over time, and a damaged line can reduce coverage or cause ponding. Extension guidance notes that faulty spray heads are a common issue with aerobic units that use spray irrigation, so they should be checked regularly.
When to call a licensed provider
- The pump, alarm, or aerator does not respond as expected when you describe it.
- The high-water alarm keeps sounding.
- The spray pattern has changed and does not return to normal after basic checks.
- Wet ground, odor, or standing liquid appears near the spray area.
- You have any doubt about electrical safety.
What to leave to the provider
- Opening or pumping the tank. Septic tanks can contain hazardous gases, so only trained specialists should service them.
- Electrical diagnosis and wiring.
- Replacing the pump. A replacement pump should match the original flow and pressure, and the provider should confirm this.
- Adjusting spray heads, valves, or lines beyond simple cleaning.
- Protecting the drainfield or spray area after a prolonged outage or pump failure.
Questions to ask the provider
- What was the pump’s flow and pressure, and does the replacement match?
- Did you test the floats, the alarm, and the aerator?
- Are the spray heads and lines clear, and is the coverage pattern normal?
- What should I watch for before the next visit?
Sources
- Oklahoma State University Extension, Aerobic Treatment System
- Oklahoma State University Extension, Benefits and Concerns Associated with Aerobic Treatment Systems
- Texas A&M AgriLife Extension, Pump Tank (L-5346)
- U.S. EPA, Resolving Septic System Malfunctions
General information only. Only a licensed provider or your local authority can diagnose and repair your system.
Last reviewed: 3 November 2026.