Why Is My Septic or Pump Alarm Going Off?

What it usually looks like

• A red light on a small box outside the house, in the garage or on the control panel
• A loud buzzer or beep that may or may not have a silence button
• Drains in the house are slow or gurgling at the same time
• The pump breaker is tripped
• A sewage odor near the tank lids or pump chamber
• The alarm sounds only during heavy rain or heavy water use, then clears

Likely causes, most common first

1. Lost power to the pump

   The alarm and the pump are often on separate circuits for exactly this reason. A tripped breaker, a GFCI that popped in the pump house, or a storm outage on Peninsula Light or Mason PUD leaves the pump dead while the alarm still screams. This is the first thing to check and the most common cause after a wind storm.

2. Stuck or failed float switch

   Pumps are started by a tethered float in the chamber. Floats get fouled with grease and solids, tangle on the cord or the pipe, or the switch inside simply fails. The pump is fine but never gets told to run. Float replacement is routine work and far cheaper than a new pump.

3. The pump itself has failed

   Effluent pumps last ten to fifteen years; grinder and ejector pumps often less because of what they handle. A burned motor, a jammed impeller from a wipe or a rag, or a seal that let water into the windings will trip the breaker or hum without pumping.

4. Blocked or frozen discharge line or check valve

   The pump pushes through a check valve and a pressure line to the drainfield, a mound, or the public sewer. A check valve stuck shut, a crushed line or a frozen above-ground section means the pump runs against a wall. Pumps that cycle on and off quickly and never lower the chamber often have this problem.

5. Too much water coming in

   A saturated drainfield in February, a leaking toilet flapper running all night, or groundwater infiltrating the tank can send more water into the chamber than the pump and the drainfield can handle. The alarm comes on during storms and clears afterward. That is a drainage or septic-system problem rather than a pump failure.

Safe things to check yourself first

• Press the silence or test button on the alarm box. The light stays on until the level drops, but the noise stops.
• Cut water use to the minimum. No laundry, no long showers, and spread flushes out. The chamber's reserve is what buys you time.
• Check the pump breaker in the panel and any GFCI outlet the pump is plugged into. Reset once. If it trips again, leave it off.
• Look at the control panel if there is one. Note any lights, the position of the switch, and whether it is set to manual, off or auto. Auto is the normal setting.
• Walk out to the tank and pump chamber lids. Do not open them unless they are designed to be opened safely; note odor, standing water or a lid that has lifted.
• If it is raining hard and the alarm has done this before in storms, note the pattern; it helps us and the septic company sort pump problems from drainfield problems.

How we diagnose and fix it

• Confirm power at the panel and the pump, test the floats and the alarm float, and read the chamber level to find out which component failed.
• Replace stuck or failed float switches and alarm floats, and set the on, off and alarm levels correctly for the chamber.
• Pull, test and replace effluent, sewage ejector and grinder pumps with the right pump for the head and the line, using Liberty and comparable units, with new check valves and unions so the next service is simple.
• Clear or replace a blocked check valve, repair a crushed or frozen discharge line, and insulate exposed sections that froze in the January 2024 cold.
• Diagnose control panel faults, replace relays and alarms, and add a visible alarm where the existing one is buried somewhere nobody hears it.
• Tell you plainly when the problem is a full tank, a flooded drainfield or a failing system, and refer you to a licensed septic pumper or designer, since we do not pump tanks or repair drainfields.

Questions people ask