St. Johns County, FL: flood zone, zoning and property lines by address
Free, no account. Or open the Florida map and tap a lot.
Flood zone by address
ParcelSheet reads FEMA's National Flood Hazard Layer at the lot: the zone, whether it is a high risk area where lenders ask for flood insurance, and the base flood elevation where FEMA lists one. FEMA's countywide study for St. Johns County has 128 FIRM panels, the newest effective December 2018; coastal V zones, where waves add to the flood, are mapped along its shore.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for a St. Johns house comes from a licensed surveyor and is often on file with the county or city building office (Building Services, Permits and Inspections).
Property lines
The parcel outline, parcel number and mapped size come from the Florida statewide cadastral (county property appraiser parcels with the Department of Revenue tax roll), so a St. Johns lot shows the same lines the property appraiser draws. St. Johns County covers about 384,422 acres of land and 141,358 acres of water.
Mapped lines are approximate. The St. Johns County Property Appraiser keeps the parcel record; a licensed surveyor sets the true corners.
An example from the county's own records: parcel 0869500030 in Saint Augustine, a lot with one house, about 40,075 square feet as mapped, the house built in 1947. Open it to see every card ParcelSheet draws for a St. Johns lot.
Zoning
St. Johns County zones its unincorporated land. ParcelSheet shows the use the property appraiser lists for the lot and links Planning and Zoning for the district, the uses it allows and the lot size it needs.
ADU and guest houses
Florida Statute 163.31771 lets local governments allow an accessory dwelling unit on a lot with a house. Whether a St. Johns lot can add one depends on its district; Planning and Zoning has the rule. ParcelSheet shows the mapped lot size and the ground's slope, the first two things the question turns on.
Septic and soil
ParcelSheet reads the USDA soil survey at the lot: the soil's name, its septic absorption rating and whether it is prime farmland. St. Johns County is soil survey area FL109, St. Johns County, Florida, last updated August 2026, on Web Soil Survey.
A new or changed septic system in St. Johns County needs a permit from the Florida Department of Health in St. Johns County, which tests the soil on the lot itself.
Setbacks
Setbacks in St. Johns County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; Planning and Zoning gives them for the lot's district. On the St. Johns shore, building seaward of the state's Coastal Construction Control Line needs a state permit.
Hazards that apply
- Sinkholes. The Florida Geological Survey lists 5 subsidence incident reports in St. Johns County (the reports). They are reports, not confirmed sinkholes; ParcelSheet does not rate a lot for sinkholes.
- Storm surge. St. Johns County has coastal V zones on its FEMA map, so storm surge reaches its shore. The county's evacuation zones are on its emergency management site; ParcelSheet shows the FEMA zone and the 3 ft sea level rise map at the lot.
- Wind. The Florida Building Code sets the design wind speed for a house in St. Johns County; the building office (Building Services, Permits and Inspections) applies it at permit.
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a St. Johns lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in St. Johns County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA's countywide flood map for St. Johns County has 128 panels, the newest effective December 2018. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in St. Johns County?
Open the Florida map, type the address, and the parcel outline from the county property appraiser shows on the map with its parcel number and mapped size. The St. Johns County property appraiser keeps the official record. Mapped lines are approximate; only a licensed surveyor sets the true corners.
What is my property zoned in St. Johns County?
Zoning in St. Johns County is set by the county for unincorporated land and by each city inside its own limits. ParcelSheet shows the use code the property appraiser lists and links the office that sets the zoning; the planning office has the final word.
Can I build an ADU in St. Johns County?
Florida Statute 163.31771 lets counties and cities allow an accessory dwelling unit, and each sets its own rules. In St. Johns County ask the zoning office for the lot's district first; ParcelSheet shows the lot size as mapped so you can see the room you have.
Do I need a septic permit in St. Johns County?
Yes. A new or changed septic system in St. Johns County needs a permit from the Florida Department of Health in St. Johns County. ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area FL109 (St. Johns County, Florida).
Next to St. Johns County: Clay County, Duval County, Flagler County, Putnam County.
The Florida map · All Florida counties · Flood zones explained · FIRM panels and LOMAs · All 50 states