Septic tanks will provide years of trouble-free service if you take care of some simple maintenance procedures. Have your system inspected yearly to see if it needs to be pumped out. Most systems need to be pumped out about every three years. It depends on the size of the system, the volume of solids in the wastewater and the number of people in your household. Your system may need to be pumped out more frequently if a garbage disposal is linked to it, or if there has been an increase in the amount of water used by your household. If you ignore the pumping out of your system at regular intervals, sludge at the bottom of the tank will rise and reduce its capacity. Scum will build up at the top of the tank and interfere with necessary bacterial actions that need to take place in order for the solids to be liquefied. This can lead to failure of the leach or drain field. Contact a professional plumber to help determine your needs.