Holding tanks are generally considered a collection and storage device with treatment actually provided at a different location. Use of a holding tank in an onsite wastewater treatment system incorporates the services of a sewage pumper/hauler and off-site treatment for the sewage generated.
The tank is a watertight device capable of storing several days of wastewater generated in the residence. Holding tanks are often prohibited except under extenuating circumstances and their use is often temporary while other options are being explored. Settling of the solids may occur during storage. However, all material in the holding tank is removed during pumping.