If the Drainfield Fails Preventive Maintenance Cleanng Tanks Conclusions Contrary to common belief, septic tanks are not maintenance free. However, properly designed septic tanks installed correctly and not overloaded with water or household grease or solids from garbage disposals normally function well for many years. Typically, septic tanks are made of precast concrete.
Some tanks have lids of three or more parts.
In addition to the floating scum, the tanks also contain liquid sewage, which eventually flows to the drainfield. Over a period of time, a sludge layer forms in the bottom of the tank. The sludge consists of the solids that remain after the anaerobic bacteria in the tank breaks down the solid wastes. The natural process of anaerobic digestion normally does quite well on its own, so no chemicals, enzymes, yeast or other additives should be routinely fed into the tanks. Normal household chemicals and occasional use of drain cleaners will not significantly affect tank operation.