A septic system receives, treats and disposes of unwanted wastewater and solids from a building’s plumbing system. Solids are partially broken down into sludge within a septic tank and are separated from effluent (water) and scum (fat, oil and grease). Effluent regularly exits the tank into a drain field where it is naturally filtered by bacteria and reentered into the groundwater. Scum and sludge must be pumped periodically and should never enter the drain field. The Septic tank should be pumped every 4-5 years.