The water supply for a multipurpose or stand-alone sprinkler system shall be provided by the public water main, private water main, private well system, or storage tank. The water supply required shall be determined in accordance with Section 6188.8.131.52 at a pressure not less than that used in accordance with Section 612.5.3. Where a water supply serves both domestic and fire sprinkler systems, 5 gpm (19 L/min) shall be added to the sprinkler system demand at the point where the systems are connected, to determine the size of common piping and the size of the total water supply requirements where no provision is made to prevent flow into the domestic water system upon operation of a sprinkler.
Where a dwelling unit water supply is from a tank system, a private well system, a pump, or a combination of these, the available water pressure shall be based on the minimum pressure control setting of the pump.
The water supply shall have the capacity to provide the required flow rate to the sprinklers for a period of time as follows:
- Seven minutes for one story dwelling units less than 2000 square feet (185.8 m2) in area. For the purpose of determining the area of the dwelling unit, the area of attached garages and attached open carports, porches, balconies and patios shall not be included.
- Ten minutes for multi-level dwelling units and one story dwelling units not less than 2000 square feet (185.8 m2) in the area. For the purpose of determining the area of the dwelling unit, the area of attached garages and attached open carports, porches, balconies, and patios shall not be included.