Short answer
A septic alarm going off usually means the water level in a pump chamber or tank has risen above its normal range. Cut back on water use, check your system's instructions, and call a licensed septic professional. Do not ignore the alarm or switch it off, and do not open the tank or electrical panels. Wastewater backing up or on the ground is an emergency.
Why is my septic alarm going off? Most of the time the answer is a high water alarm: water has reached a float that sits above the normal working level. The cause could be a pump or float problem, a power problem, a clogged filter or simply a lot of water in a short time. You cannot tell which from the box on the wall, so the job is to protect the system, gather facts and get the right person out.
This guide covers what a septic tank alarm beeping usually means, what to do straight away, what to leave alone, and what to tell the company. It is general information. Your alarm panel, the manufacturer's manual and your installer's instructions come first.
What a septic alarm usually means
Not every system has an alarm. The Montana Department of Environmental Quality homeowner guide says that if your system has a pump chamber, you should have an alarm. The panel may be in a basement or on the outside of the house near the system.
The same guide explains what happens. If the liquid level in the pump chamber reaches the alarm float, whether because of a faulty pump, floats, circuit or another problem, the alarm light and buzzer start. That is a high water alarm. The chamber has some reserve storage above the alarm, but the reserve is limited, which is why the next steps are about water use and speed.
An alarm can also be tied to other parts. The Montana guide describes an alarm as a critical part of an effluent filter installation, because it shows when the filter needs cleaning. Advanced treatment systems may have their own alarm functions. The manual for your specific unit explains what each light or tone means.
What to do right away
- Note what you see and hear. Which light is on, whether the buzzer is sounding and the time. Take a photo of the panel and any label on it.
- Reduce water use now. The Montana guide says that using water conservatively, which means avoiding baths, showers and clothes washing, should give the reserve storage enough time for the problem to be corrected. Hold off on the dishwasher and long running taps too. Use only the water you have to.
- Check for emergency signs. Wastewater backing up in the house, or wet ground and sewage at the surface, change the situation. See the emergency section below.
- Find your instructions. Look for the manufacturer's manual, a sticker on the panel, your installer's paperwork or your service company's number. Follow what they say about this specific alarm.
- Call a licensed septic professional. Say it is a high water alarm and that you have reduced water use. Alarms are time-sensitive, so say that on the call. If you do not have a company, the local health department can usually give you names.
- Keep reducing water until you hear back. A quiet alarm does not mean the water level has dropped.
Silencing the buzzer is not fixing the problem
Many panels have a button that silences the buzzer. The Montana guide says pushing the reset light on the panel silences the alarm. Silencing it can be reasonable if the instructions say so, because a constant buzzer is hard to live with while you wait for service. But the water level that triggered it has not changed, and the warning light usually stays on.
The University of Maryland Extension homeowner guide says owners of advanced treatment systems should not turn off the alarm, and should not turn off the electricity to save money, since that can greatly reduce the effectiveness of the system and let solids clog the drainfield. Do not disconnect the alarm, remove its power or leave it silent and forget about it. If the alarm stops by itself, still call and report that it happened, because the cause may still be there.
What not to do
- Do not open the tank, the pump chamber or any lid or riser. The Montana guide says directly: do not enter the pump chamber. Gases inside pump chambers are poisonous and the lack of oxygen can be fatal. Treat every tank, chamber and cover as off limits.
- Do not open electrical panels or handle the pump, floats or wiring. The Montana guide says to turn off the power supply at the circuit breaker and unplug all power cords before handling a pump or floats, and that service of pumps and other electrical equipment must be done by an experienced person. Leave this to the service company.
- Do not keep using water as normal. Extra water can push a full chamber toward overflowing.
- Do not turn off the power to the system or disconnect the alarm. See above.
- Do not add chemicals or additives to the tank. The University of Maryland Extension guide says it is not necessary to add enzymes or bacteria, that additives do not improve performance and that some can cause solids to leave the tank and clog the drainfield.
- Do not wait to see if it goes away. Report it either way.
Common causes of a high water alarm, in general terms
The Montana guide lists some things to check before calling for repair. Every item below is for a professional to check, or for you to mention on the phone.
| Possible cause | What it can mean | Who handles it |
|---|---|---|
| Tripped breaker or blown fuse | The pump has lost power. Montana notes the pump should have its own circuit. | Tell the company, and ask before resetting anything. |
| Unplugged pump or float cord | A plug-in connection may not be making contact. | Service professional |
| Floats tangled or covered in debris | The pump may switch off or never switch on when it should. | Service professional |
| Failed pump or float switch | The chamber fills because the water is not being moved on. | Service professional |
| Clogged effluent filter | The filter needs cleaning, and an alarm is often how it shows. | Service professional |
| Large volume of water | Lots of laundry, a leak or a running fixture can overload the system. University of Maryland Extension says leaks can overload it. | You can help by reducing and fixing leaks, then call anyway |
| Wet drainfield or too much water on the area | EPA says excess water slows or stops the treatment process. | Service professional and local authority |
Do not try to lift floats out of a chamber or clean them yourself. The Montana guide describes those steps for people who first turn off the power and unplug cords, and it warns against entering the chamber. It is safer to report what you notice and let the company decide.
What to tell the service company and what to record
A good description saves a visit. Write down:
- The date and time the alarm started, and whether it stopped or came back.
- Which light or sound, and a photo of the panel and its label, including the brand if shown.
- Recent heavy water use: laundry, guests, a long shower, a running toilet or tap, a leak.
- Any slow drains, gurgling, odor or wet spots outside. See the signs your septic system is failing.
- Whether you have noticed a tripped breaker in the house panel.
- The date of the last pumping, inspection or service, and the type of system if you know it. See types of septic systems.
- What you have done so far, such as cutting water use.
Ask the company what they found and what they did, and ask for a written service report. EPA tells owners to keep maintenance records, so add the report to your system folder.
How alarms differ by system type
| System | What to expect |
|---|---|
| Gravity-fed conventional system | May have no alarm at all, since the Montana guide ties alarms to systems with a pump chamber. An effluent filter on the tank outlet may have an alarm. |
| Mound, sand filter, drip | EPA says these use pump chambers or dose tanks and, for drip, electrical power. These may have a high water alarm in the pump or dose chamber. |
| Aerobic or other advanced treatment unit | Has mechanical parts and may have a control panel. University of Maryland Extension says to keep the service contract and not to switch off the alarm. The manufacturer's manual explains the alarm signals. |
If you do not know which type you have, read types of septic systems and ask your health department for the as-built drawing. Systems with pumps and float switches are generally inspected once a year, according to EPA, so a service visit can include testing the alarm.
When a septic alarm is an emergency
Treat it as an emergency if sewage is backing up into toilets, sinks or tubs, if wastewater is on the ground, or if the alarm is on and the situation is getting worse despite reduced water use. EPA's page on what to do if your system fails says to avoid contact with sewage because it may contain harmful pathogens, and to contact your local health department or regulatory agency for guidance. It also lists a local septic service provider and your onsite wastewater regulatory agency as people to call. Keep children and pets away from wet areas, and follow your health department's advice on cleanup.
Call the septic company and tell them it is an emergency. If you cannot reach anyone, call the local health department.
Reducing the chance of a repeat
- Spread laundry across the week and fix leaking toilets and taps.
- Flush only human waste and toilet paper. University of Maryland Extension says wipes can clog septic tank filters, pumps and drainfields.
- Keep the service schedule. See septic tank pumping cost for what affects the price.
- Keep vehicles off the drainfield, and keep rainwater and sump discharge away from it.
What to look up where you live
EPA says it does not regulate single-family home septic systems. The rules sit with states, tribes and local governments, and local health departments typically issue permits. Look up:
- County or local health department, or environmental health office. Your permit and as-built drawing, approved service providers, and what to do about sewage on the ground.
- State environmental or health agency. Rules for advanced treatment systems and service providers.
- State licensing board. Whether the person who services your pump or panel must be licensed or certified.
Note for Canadian readers. Provinces and territories regulate onsite wastewater, often with municipalities or regional health units. Start with your municipality or health unit and your provincial ministry, and check the current rules for your province.
For septic, plumbing and drain company owners
An alarm call is usually urgent and often comes after hours, so a missed call is a lost job. Answering systems and quick follow-up matter as much as advertising. See our guides to the plumbing answering service and septic and drain customer follow-up templates, or book a free call.
