In the absence of a municipal water supply or where a prescribed NFPA pump and tank arrangement is not feasible, a private well/pump system is allowed. This system can serve either independently as the fire protection water supply or as a combination supply for domestic water, irrigation and fire protection. From a reliability standpoint, it is generally preferred that it be a combination system.

Private well/pump systems that provide water to fire protection systems are not considered “fire pumps” in the traditional sense and are not subject to the requirements of NFPA 20. The well/pump must be designed and installed to meet the fire protection system demand both in gallons-per-minute (GPM) and pressure in pounds per square inch (PSI).

In situations where there may be a low flow rate for domestic use and a higher flow rate for fire protection demands, wells are allowed to have multiple pumps within the same casing.

The well/pump must incorporate a variable speed or frequency drive/controller that senses losses in system pressure and adjusts the pump speed to maintain a constant pre-set pressure.