Sounds like you have a problem.
I found this.You might want to get that thing check out before you have major problems.
SEPTIC TANK ALARMS
Have you ever heard a buzzing sound coming from your furnace room? That buzzing sound may be coming from your septic tank alarm. 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 your 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