/ Septic alarms
Septic alarm going off? Here is what to do.
A septic alarm means the water level in your pump chamber or tank is higher than it should be. It is a warning, not a disaster, if you act on it today.
By Anthony Wilson, founder · Updated November 2026
If you have a pressure distribution, mound or aerobic treatment unit (ATU) system, which is most of the plateau homes in King and Snohomish County, your system has a pump chamber with an effluent pump, a set of floats and a control panel with an alarm. When the alarm goes off, the panel is telling you that wastewater in the chamber has risen above the normal level. Something is stopping the pump from moving it out to the drainfield, or more water is coming in than the pump can handle.
The alarm is designed to give you time. Most pump chambers hold a reserve above the alarm float, often enough for a day of careful use. Use that time well and you usually avoid a backup.
What to do right now
- Silence the alarm. Most panels have a button or switch marked “silence”, “test/normal/silence” or similar. This stops the noise but does not fix anything. The light usually stays on.
- Stop using water. No laundry, no dishwasher, no long showers, and flush only when you have to. Every gallon goes into the chamber that is already full.
- Check the breaker. Look at your electrical panel for the septic pump breaker. If it has tripped, reset it once. If it trips again, leave it off and call us. That points to a pump or wiring fault.
- Wait 20 to 30 minutes. If the pump was just slow to catch up, for example after heavy rain or a lot of laundry, the alarm may clear on its own once the level drops.
- Call if it does not clear. If the alarm comes back on, keeps sounding, or you see water around the lids, call us. Our phones are answered 24/7.
Do not open the pump chamber and reach in, and do not try to reset or pull the pump yourself. Pump chambers contain sewage gases and live electrical equipment.
What usually causes a septic alarm
A stuck or failed float
Floats tell the pump when to turn on and off. They can tangle with each other, get stuck on the pump or a pipe, or simply wear out. A stuck “on” float means the pump never starts. This is one of the most common calls we get, and often a quick fix. One customer’s alarm turned out to be a float hung up on the pump; we freed and adjusted it, inspected the system, and they did not need pumping at all.
A failed effluent pump
Effluent pumps typically last years, but they do wear out, especially if they cycle a lot or have been running against a clogged filter. If the breaker keeps tripping or you hear the pump hum without moving water, the pump may need replacing.
A clogged effluent filter or screen
Many systems have a filter or screen that stops solids from reaching the pump and drainfield. When it clogs, water backs up behind it. Cleaning it regularly is one of the cheapest ways to prevent alarms, and it is included free once a year in our Septic Maintenance Plan.
Groundwater or rainwater getting in
In our wet winters, an alarm that only goes off after heavy rain usually means water is leaking into the tank or chamber through a lid, riser joint or crack, or that downspouts or surface water are draining toward the system. The pump cannot keep up with the extra volume.
A drainfield that cannot take more water
If the pump runs but the alarm keeps coming back, the problem may be downstream: a clogged line, a stuck valve or a saturated drainfield. That needs a proper diagnosis before anyone replaces parts.
How we fix it
When we come out for an alarm, we find the cause before recommending anything. We check the panel and breaker, the floats, the pump and the filter, look for water getting in, and if needed pump the chamber down so we can see what is happening. Many alarms are a float, a filter or a breaker, not a new system. Repairs carry the Septic Response Promise: a one-year warranty on most repairs. See our septic repair and 24/7 emergency service pages.
How to prevent the next one
- Have the filter cleaned and the floats and pump checked once a year.
- Keep the tank pumped on schedule (every three to five years for most homes; see how often to pump).
- Spread laundry out over the week.
- Send downspouts and driveway runoff away from the tank and drainfield.
- Make sure lids and risers are sealed so rainwater cannot get in.
- Keep up with your county inspections. Pressure, mound and ATU systems are on a shorter schedule in both King County and Snohomish County.
Quick answers
Can I keep using my toilet when the septic alarm is going off?
Use as little water as possible. Flushing occasionally is usually fine for a few hours, but skip laundry, dishwashers and showers until the alarm clears or we have checked the system.
Why does my septic alarm go off when it rains?
Usually because rainwater or groundwater is getting into the tank or pump chamber through a lid, riser joint or crack, or because runoff drains toward the system. The pump cannot keep up with the extra water.
How long can I wait after a septic alarm?
Most pump chambers have some reserve space above the alarm, often enough for about a day of very light use. Do not wait longer than that. If the alarm does not clear within half an hour of cutting water use, call.
How much does it cost to fix a septic alarm?
It depends on the cause. A stuck float or clogged filter is a small repair; a new effluent pump costs more. We diagnose the cause first and give you the price before doing the work.
Is a septic alarm an emergency?
Not yet, but it becomes one if you ignore it. Cut water use, check the breaker, and call if it does not clear. We answer 24/7 in King and Snohomish County.