Clay County

Permits for ADUs on parcels in unincorporated Clay County are issued by the Clay County Building Department, working with the Department of Planning & Zoning on zoning-compliance review. Clay County has five incorporated municipalities (Green Cove Springs, Orange Park, Keystone Heights, Penney Farms, Lake Asbury in process). Unincorporated Clay contains large suburban and semi-rural areas including Fleming Island, Oakleaf, Middleburg, Lake Asbury, and Doctors Inlet.

Process overview: An ADU on an unincorporated Clay parcel is permitted as a combined planning/building permit. Typical workflow: zoning-compliance review (lot size, setback, septic feasibility if unsewered), submission of construction drawings under Florida Building Code 2023, building plan review, wind-load review (Clay sits in approximately the 130-140 mph ASCE 7-22 ultimate design wind-speed zone — Risk Category II residential), issuance, construction with inspections, and certificate of occupancy. Floodplain parcels along the St. Johns River, Black Creek, and tributary corridors require elevation-certificate review. Septic-system parcels require FDOH Clay County office review.

Impact fees: Clay County levies transportation, schools, fire-rescue, and parks impact fees on new residential units. The Clay County School District impact fee is substantial given the school-age demographic growth of the Orange Park / Fleming Island / Oakleaf corridor. ADU additions in unity-of-title arrangements receive reduced fees compared to detached primary residences. (schedule)

The Clay County Property Appraiser maintains parcel-level assessment records for all real property in Clay County. ADU additions are assessed as improvements to the host parcel; Florida's Save Our Homes 3% cap applies to the homesteaded primary residence portion, with the new improvement assessed at just value on completion.

Assessment policy: ADU additions are assessed at just value on completion; host homestead portion continues under Save Our Homes cap. No county-level ADU abatement or incentive.

Clay County administers floodplain, wetland, and St. Johns River corridor overlays. Clay does not have Atlantic-Gulf coastline but has extensive St. Johns River and Black Creek frontage. St. Johns River Water Management District jurisdiction covers the county's wetland and stormwater permitting. Camp Blanding Joint Training Center (Florida Army National Guard) occupies significant territory in southern Clay and imposes airspace/noise-compatibility considerations on nearby parcels.

• FEMA Special Flood Hazard Areas (SFHA) — Clay participates in the NFIP. Parcels along the St. Johns River, Black Creek, Peters Creek, and Doctors Lake corridors face Zone A or AE designations. ADU construction in a mapped floodplain requires elevation-certificate review. Hurricane Irma (2017) produced significant Black Creek flooding that informed post-event map updates; Hurricane Ian (2022) produced additional flood impact.
• St. Johns River Water Management District Environmental Resource Permits — Clay sits within SJRWMD jurisdiction. ADU site work affecting jurisdictional wetlands, adding a threshold area of impervious surface, or altering stormwater flow requires SJRWMD ERP. Clay's high water table and extensive wetland features on rural parcels make wetland delineation a common pre-construction requirement.
• Hurricane Wind Zone — approximately 130-140 mph ultimate design wind speed — Clay sits in approximately the 130-140 mph ASCE 7-22 ultimate design wind-speed zone (Risk Category II residential). Inland relative to Atlantic/Gulf coastal counties but still requiring hurricane-rated construction details.
• Camp Blanding Joint Training Center — airspace and noise compatibility — Camp Blanding (Florida Army National Guard) occupies much of southern Clay. Parcels within the noise-compatibility and accident-potential zones face additional review and, in some sub-zones, restrictions on residential density and occupancy types. An ADU on an affected parcel may require military-compatibility review.
• Jennings State Forest and Conservation Lands — Jennings State Forest and related conservation lands occupy portions of northwestern Clay. Parcels adjacent to these lands face additional habitat-compatibility review and, for parcels inside Habitat Conservation Plan areas, species-protection requirements (gopher tortoise, red-cockaded woodpecker in some pine-flatwoods areas).