Pinellas County

Permits for ADUs on parcels in unincorporated Pinellas County are issued by Pinellas County Development Review Services. Because unincorporated territory is fragmented and often adjoins city limits, pre-application confirmation of jurisdiction (city vs. county) is the critical first step — a parcel a block from an incorporated boundary is commonly misclassified by applicants. Incorporated cities inside Pinellas (St. Petersburg, Clearwater, Largo, Pinellas Park, Dunedin, Tarpon Springs, Oldsmar, Safety Harbor, Seminole, Gulfport, Madeira Beach, Treasure Island, Redington Beach, Redington Shores, North Redington Beach, Indian Shores, Indian Rocks Beach, Belleair, Belleair Beach, Belleair Bluffs, Belleair Shore, Kenneth City, South Pasadena, St. Pete Beach) handle their own ADU permits.

Process overview: A Pinellas County ADU permit is a combined planning/building review: (1) jurisdictional determination (is the parcel in unincorporated Pinellas, a city, or on an incorporated boundary line); (2) zoning verification that the parcel's district permits an ADU and confirmation of size, setback, height, and owner-occupancy conditions; (3) site-plan review with coastal construction review for parcels seaward of the Coastal Construction Control Line (CCCL); (4) building-code plan review against the Florida Building Code (8th Edition, 2023) including coastal high-hazard and wind-exposure provisions (most of Pinellas is Category C or D exposure and faces 160+ mph ultimate design wind speeds on the barrier islands); (5) mechanical/electrical/plumbing sub-permits; (6) flood-zone compliance review for parcels in SFHA; (7) issuance, construction with inspections, and Certificate of Occupancy.

Impact fees: Pinellas County assesses school, transportation, parks, and public-safety impact fees on new residential units; ADUs on existing single-family parcels receive a reduced assessment but not a waiver. Exact fees by district and unit size are published in the county's adopted fee schedule. (schedule)

The Pinellas County Property Appraiser maintains parcel-level assessment records for all real property in Pinellas County, including parcels within incorporated cities. ADU additions are assessed as improvements to the host parcel. Florida does not permit separate tax-parcel creation for an attached ADU; a detached accessory unit may receive its own improvement line on the tax card but remains on the host parcel number. Florida's Save Our Homes homestead assessment cap (Art. VII § 4(d), FL Const.) limits annual increases to 3% or CPI, but an improvement is added at full just value in the completion year.

Assessment policy: ADU / accessory-structure additions are captured via shared permit data with Development Review Services. Homestead exemption continues on the owner-occupied primary dwelling; the ADU portion does not qualify for homestead unless occupied by an owner. § 193.703 FS 'granny-flat' assessment reduction (up to 20% of just value for additions housing a 62+ parent or grandparent) is available upon application.

Pinellas County administers coastal, flood, historic, and airport overlays that cut across incorporated and unincorporated jurisdictions. The county's peninsular geography and barrier-island exposure make coastal construction and flood-hazard overlays especially consequential for ADUs — the majority of Pinellas parcels west of US 19 carry AE or VE flood-zone designations.

• FEMA Special Flood Hazard Areas (SFHA) — Pinellas is heavily flood-mapped. VE (velocity / wave) zones occupy the immediate shoreline of the Gulf barrier islands; AE zones extend inland across most of the western half of the county. ADUs in VE zones require pile-foundation or breakaway-wall construction with finished floor above BFE; AE-zone ADUs require elevation, flood vents, and flood-resistant materials. This is often the largest single cost driver for a coastal-Pinellas ADU project.
• Coastal Construction Control Line (CCCL) — The Florida DEP maintains a CCCL seaward of which new construction requires a state CCCL permit in addition to local permits. Portions of Pinellas's Gulf-front parcels (mostly in incorporated beach municipalities) are seaward of the CCCL; an ADU on such a parcel adds a state permit step with engineered-foundation review.
• St. Petersburg-Clearwater International Airport Noise & Approach Overlay — Parcels under the approach/departure surfaces of PIE face height restrictions and, in some cases, noise-attenuation construction requirements. A two-story ADU may be affected where a one-story primary dwelling is not.
• Historic Districts & Individually-Listed Historic Resources — Several Pinellas municipalities operate historic preservation boards with design-review authority over exterior alterations and new construction in mapped historic districts. A detached ADU in a historic district typically requires Certificate of Appropriateness (COA) review in addition to the standard building permit; this is a city-level process but is noted here because it cuts across the municipal boundary pattern.
• Wildland-Urban Interface (WUI) — Practical WUI exposure in densely urbanized Pinellas is limited; the provision is noted for completeness. Pinellas's larger insurance-underwriting pressure is hurricane-wind and storm-surge, not wildfire.