Septic pumping is necessary to remove the sludge that settles to the bottom of the treatment tank. It is also used to remove the scum layer that is composed of grease oils and fats. Bacteria cannot break down the scum layer. If the sludge enters the drain field, the crushed stone and soil will eventually become impermeable and effluent will seep to the surface.
The installation of filters on the outflow baffles will eliminate the outflow of sludge in a properly functioning system. If filters are installed, they should be inspected and cleaned annually. Some filters may need to be cleaned sooner depending on the use.