St. Johns County, FL Building Safety: Fire Sprinkler Requirements (2026)

Section 6.03.02 of the Land Development Code sets a sliding scale of fire protection water supply requirements for new development in unincorporated St. Johns County, keyed to how many dwellings are involved and how far the site sits from a central utility provider, using two thousand six hundred forty feet, half a mile, as the dividing line. For developments of one to ten detached single-family or two-family dwellings within half a mile of a central utility provider, subsection A.1 requires a pressurized fire hydrant system connected to that provider.

Once a development crosses the half-mile threshold, subsection A.2 gives the applicant a choice: option (a) is an alternative water supply under Section 6.03.04 combined with a residential sprinkler system installed in every dwelling unit to NFPA 13D, the standard for sprinklers in one- and two-family dwellings and manufactured homes, in whatever edition the Florida Fire Prevention Code currently adopts; option (b) is still a pressurized hydrant system under Section 6.03.03, which may draw on a non-potable water supply. Larger subdivisions of eleven or more dwellings face the parallel rule in subsection B.2: beyond half a mile, the hydrant system must connect to the central provider or be supplied per NFPA 24, or, again, every unit gets an NFPA 13D sprinkler system.

Subsection A.3 lets the County Administrator approve variations from these standards on a showing of good cause where an applicant's alternative meets the general intent of the fire protection article. Section 6.03.01 adds a baseline separately: structures must keep ten feet of separation from each other or be protected by an NFPA 13-compliant system or extra hydrant flow.