Indicators of a full septic tank include slow moving drains, unpleasant odors and swampy ground surrounding the tank or drain field. Servicing the tank at regular intervals, before these signs develop, helps to ensure the tank provides long-term useful service.
Waste from the home drains into the tank, where it separates into three layers. A sludge layer of materials heavier than water forms on the bottom of the tank. A scum layer of fats and grease forms on top. Between the scum and sludge is the working volume of the tank, composed primarily of water. When the layers of solid material begin to fill the tank, they leak back into the drain line from the home, causing clogs, sewer gas odors in the home or drain field failure. Water on top of the ground is an indicator the drain field is failing.
Homeowners who use septic systems should take steps to protect the tank. Water conservation helps to reduce stress on the system. Flushing household waste such as diapers, pet litter, cooking grease and excess food increases the buildup of solid materials and the frequency of pumping. Drain cleaners and other household chemicals interfere with the natural biological action in the tank.