All septic systems that use a pump to move wastewater from a septic pump tank to a drainfield or mound have an alarm installed in the house. The alarm goes off when wastewater is not being pumped from the septic pump tank to the drainfield or mound. When the alarm goes off, you have approximately 400 gallons of capacity in your septic pump tank before wastewater starts to back up into your basement. When you hear the septic tank alarm buzzing, you should call a septic service company as soon as possible. 

Some common causes that may trigger your septic tank alarm are:
1. The pump has broken (average pump life is 10 years)
2. Power to the pump has been disconnected
3. Wastewater is coming into the tank faster than it can be pumped to the drainfield. 
4. The septic tanks are leaking and surface water or groundwater is entering into the tanks, thus during heavy rain storms your pump can’t keep up. 
5. The pipes in your mound or drainfield are plugged with debris or frozen water, and water cannot pass through the pipes. 
6. False alarm. 

In addition to septic tank alarms, a company in Maine by the name of Aeration systems manufactures a leach field monitor called the Septic Sentry. By measuring the level of wastewater in the field directly, the Septic Sentry provides an early warning against leach field failure.