Fire Service Planning for Water
Most municipal subdivision regulations require six-inch water mains capable of delivering at least 500 gpm at a residual pressure of 20 psi, and they require that hydrants be installed no more than 1,000 feet apart or at an average of 500 feet from structures. Desired fire hydrant spacing for residential areas is to have fire hydrants generally spaced on 500-foot centers. For commercial and industrial areas, fire hydrant spacing should be reduced. Some commercial and industrial occupancies with needed fire flows exceeding 3,500 gpm may need hydrants to be spaced much closer in order to provide enough hydrants to meet the needed fire flow. With the use of GPS equipment, insurance companies can more accurately determine the exact distance of a structure from a fire hydrant and charge the correct property insurance rate. Public and private water utility districts operating within a city and its urban growth area are not required to comply with municipal subdivision regulations that require the installation of fire hydrants. There often is a serious disconnect between municipal planning and the provision of water by utility districts and private utility companies. It is somewhat ironic that only the largest utility, usually the electric system or the telephone company, was required to participate in the development of the 20-year urban growth plan required by Public Chapter 1101, and utilities are not required to comply with the city’s growth plan.

According to a former UT County Technical Assistance Service fire consultant, water systems typically can be designed and installed for fire protection with an increase in total project cost of only 4 to 10 percent over a potable system only. This is another area that will pay huge dividends over the next 10 to 15 years. Water systems and community development planning is a complex subject that local governments cannot afford to ignore. It is vital, not only for safety and property conservation, but also for the continued economic growth of a region.

Many communities in Tennessee want a water supply with six-inch or larger, depending upon the needed fire flow, water mains and community-wide fire hydrants. They want improved fire service to save lives and property; however, they often are opposed to rate increases to fund needed system upgrades to improve water service.