Check FEMA flood zone designation for a parcel before permitting or siting a septic drainfield

Steps

1. Query the FEMA NFHL MapServer's flood hazard zone layer at hazards.fema.gov/arcgis/rest/services/public/NFHL/MapServer/{layerId}/query with a geometry point for the parcel and f=json.
2. Read the FLD_ZONE and ZONE_SUBTY attributes from the response to determine if the parcel is in a Special Flood Hazard Area (e.g. Zone AE, VE) where septic siting rules tighten.
3. If the query returns no features, call the NFHL availability layer to confirm whether the county even has effective digital flood data (some rural counties are unmapped).
4. Pull the base flood elevation attribute where present to compare against the proposed drainfield elevation.
5. Cross-check results against your state's specific septic-in-floodplain setback rule, since FEMA data flags the hazard but doesn't itself regulate septic siting.