What is Fire Flow? Fire flow is water available for the fire department to use to extinguish a fire. Fire flow can come from fire hydrants connected to a municipal water supply, water district, or water association or it may come from a stand alone system on your property.
For residential and personal storage buildings fire flow is only required once you reach a certain square footage. That square footage calculation includes all usable spaces in the building, even if they are unfinished or just for storage.
For residences, fire flow is required if the building is larger than 4000 square feet (including all spaces – garages, basements, bonus rooms etc).
For detached personal storage buildings, fire flow is required if the building is larger than 2500 square feet.