Combined System

In this system of water supply, pumping and gravity system is combined. The system is quite adaptable and can be used in all circumstances. In this system, the treated water is pumped and stored in an elevated distribution reservoir or tank and from the distribution tank; it is fed to the distribution system through the action of gravity.

Pump works at constant and convenient schedule and the pressure can be maintained uniformly during the supply. At the time of higher demand, further demand is supplemented through distribution reservoirs. Even at the time of power failure, the supply can be maintained without any interruption. Because of detention of treated water in the distribution reservoir, quality of water improves. The excess water during low demand period is stored in the distribution reservoir.

If the source of supply is at low elevation, then by small lift pumps, the water is taken to the treatment units. Or else, if the source is at higher elevation, then water flows to the treatment plant through gravity. The combined method can be appropriate in all types of topography and circumstances; hence, it is universally accepted and used.