Like an ordinary septic tank, sludge must be removed from your system periodically (such as once every two years). Your service provider will measure sludge accumulation on each service visit and provide guidance to help arrange for a septic tank pumping company to provide this service when necessary. Pump-out frequency depends on waste stream strength and use. Please consult with your service provider to help determine the frequency that is best for you. Also, please note: use of a garbage disposal usually increases pump-out frequency.