ADU Pass
Alachua County
ADU Pass helps homeowners in Alachua County, Florida navigate the permit paperwork for building an accessory dwelling unit. We cover 10 cities and 21 ZIP codes in this county.
Map
County ADU details
County ADU ordinance
Alachua County (county seat Gainesville, home of the University of Florida) regulates accessory dwelling units on unincorporated parcels through the Alachua County Unified Land Development Code (ULDC). Alachua has been notably more progressive on ADU policy than most Florida counties, partly driven by Gainesville's sustained student-and-university-adjacent rental demand. The ULDC permits ADUs in most residential zones subject to lot-size, setback, and occupancy conditions; Gainesville city code similarly permits ADUs in most residential districts and has an active ADU-incentive program for certain neighborhoods. County population approximately 290,000 including Gainesville. Florida has no statewide ADU preemption; § 163.31771 FS is permissive only. Pending SB 48 / HB 313 (2026 session) would establish a statewide ADU floor with a December 1, 2026 conformance deadline if enacted.
Code citations:
- Alachua County Unified Land Development Code (ULDC)
- Florida Statutes § 163.31771 — Accessory Dwelling Units
- Alachua County Comprehensive Plan — Housing Element
State-floor overlay: Florida has no statewide ADU preemption as of April 2026. § 163.31771 FS is permissive only. Pending 2026 bills (SB 48 / HB 313) would impose a statewide floor; Alachua's ordinance is already more permissive than the likely statutory floor, so conformance work would be modest (December 1, 2026 deadline in current drafts).
Adopting body: Alachua County Board of County Commissioners
County permitting (unincorporated parcels)
Permits for ADUs on parcels in unincorporated Alachua County are issued by the Alachua County Growth Management Department. Alachua has nine incorporated municipalities (Gainesville, Alachua, Archer, Hawthorne, High Springs, La Crosse, Micanopy, Newberry, Waldo); Gainesville is by far the largest. Unincorporated Alachua includes substantial suburban growth corridors west and south of Gainesville (Haile, Tioga, Jonesville, Kanapaha), rural-residential and agricultural areas in eastern and northern county, and Paynes Prairie-adjacent areas in the south.
Process overview: An ADU on an unincorporated Alachua parcel is permitted as a combined planning/building permit. Typical workflow: zoning-compliance review, site-plan and construction-drawing submission under Florida Building Code 2023, wind-load review (Alachua's inland-central location sits in approximately the 130-140 mph ASCE 7-22 ultimate design wind-speed zone — Risk Category II residential), plan review, issuance, inspections, and certificate of occupancy. Floodplain parcels along the Santa Fe River, Newnans Lake, and Paynes Prairie edge require elevation-certificate review. Karst-terrain parcels (sinkhole-prone, common in Alachua) may require additional geotechnical review.
Impact fees: Alachua County levies transportation, schools, fire-rescue, and parks impact fees on new residential units. The Alachua County School District impact fee is substantial. ADU additions receive reduced rates in most categories; Gainesville (city) has an ADU-specific fee reduction program in designated neighborhoods. (schedule)
County assessor
The Alachua County Property Appraiser maintains parcel-level assessment records for all real property in Alachua County, including parcels within Gainesville and the eight other incorporated cities. ADU additions are assessed at just value on completion; Florida's Save Our Homes 3% cap applies to homesteaded primary residences. Gainesville's rental-heavy market produces substantial non-homestead inventory reassessed annually at just value.
Assessment policy: ADU additions assessed at just value on completion; homesteaded host portion continues under Save Our Homes cap. No county-level ADU abatement or incentive, though Gainesville (city) operates an ADU-oriented rebate program tied to its affordable-housing policy.
County overlays (6)
Alachua County administers an environmentally-focused overlay portfolio. Paynes Prairie Preserve State Park and adjacent conservation lands, the Santa Fe River (northern county boundary), Newnans Lake, and karst-aquifer springshed protection overlays constrain ADU siting in affected areas. Suwannee River Water Management District and St. Johns River Water Management District jurisdictions both apply depending on watershed — an unusual dual-district situation.
- Paynes Prairie Preserve State Park buffer and surrounding Alachua Sink overlay — Paynes Prairie occupies approximately 22,000 acres south of Gainesville. Parcels adjacent to the preserve face additional habitat-compatibility review and, for parcels within the Alachua Sink drainage, enhanced water-quality protection requirements.
- Santa Fe River and Newnans Lake floodplain overlays — Alachua participates in NFIP. Parcels along the Santa Fe River (northern county boundary), Newnans Lake, Lake Santa Fe, and tributary corridors face Zone A or AE designations. ADU construction in a mapped floodplain requires elevation-certificate review.
- Karst / Springshed Protection Overlays — Alachua sits on the Floridan Aquifer with extensive karst features (springs, sinkholes, sinking streams). The county's springshed-protection overlays impose enhanced septic-system design requirements and limits on stormwater-runoff in springshed-contributing areas. ADU site work on karst parcels may require geotechnical investigation (to identify sinkhole risk) in addition to standard stormwater and septic review.
- Suwannee River Water Management District and St. Johns River Water Management District — Alachua's unusual position on the watershed divide places western and northern county within SRWMD jurisdiction and eastern / southern county within SJRWMD jurisdiction. ADU site work affecting wetlands or altering stormwater may require ERP from the appropriate district; applicants should verify which district applies to a given parcel.
- Hurricane Wind Zone — approximately 130-140 mph ultimate design wind speed — Alachua's inland-central location sits in approximately the 130-140 mph ASCE 7-22 ultimate design wind-speed zone (Risk Category II residential). Less severe than coastal counties but still requiring hurricane-rated construction details.
- University of Florida adjacency — Gainesville Comprehensive Plan Rental Permit Program — Gainesville (city) operates a Rental Permit Program that affects rental ADUs within city limits. Unincorporated Alachua parcels immediately adjacent to campus (Haile, Tioga, suburbanized areas) do not fall under the city's rental-permit program but may face informal market comparison pressure.
Known county issues (3)
- policy-review — Both bills would impose a statewide ADU floor. Alachua's ordinance is already more permissive than the likely statutory floor, so conformance work is expected to be modest (December 1, 2026 deadline in current drafts).
- other — Gainesville's University of Florida-centered rental market (approximately 60,000 students) creates sustained demand for bedroom-scale rental units. ADUs in university-adjacent neighborhoods (unincorporated west Gainesville, Haile, Tioga, and within Gainesville city limits) often achieve rental yields that justify construction costs despite higher absolute construction costs than rural Florida. This is unusual among Florida counties.
- other — Alachua's Floridan Aquifer karst geology means sinkhole risk is elevated across much of the county. ADU construction on a parcel with suspect geology may require ground-penetrating radar or other geotechnical investigation; discovered voids or weak zones can materially increase foundation costs.
Florida state — ADU law and programs
State ADU law
Florida does NOT currently have a statewide ADU preemption law in effect. Florida Statutes § 163.31771 (enacted 2004, last amended 2020) is permissive — it authorizes local governments to adopt ADU ordinances but does not require them to. ADU rules are therefore set municipality-by-municipality: Miami-Dade, Orlando, St. Petersburg, Tampa, and a growing set of Florida cities have their own ordinances; many smaller counties and cities still prohibit or restrict ADUs by default. A preemption bill (SB 48 / HB 313) is pending in the 2026 legislative session and is likely to pass given that its 2025 predecessor cleared the Senate 37-0 and House 97-10 before dying on a procedural amendment dispute.
- Florida Statutes § 163.31771 — Accessory dwelling units — Permissive (not mandatory) statute. Defines an ADU as 'an ancillary or secondary living unit, that has a separate kitchen, bathroom, and sleeping area, existing either within the same structure, or on the same lot, as the primary dwelling unit.' Authorizes — but does not require — local governments to adopt ordinances allowing ADUs in single-family residential zones. Contains no size caps, no owner-occupancy rules, no HOA preemption. All substantive rulemaking is local.
State financing programs
Florida Housing Finance Corporation (FHFC) does not operate an ADU-specific state loan or grant program. FHFC's primary affordable-housing lever at the ADU tier is the State Housing Initiatives Partnership (SHIP), which distributes state documentary-stamp-tax revenue to all 67 counties and 52 entitlement cities for locally-administered housing programs — some of which may fund ADU construction at the local level (notably Orange County's Affordable ADU Loan Program, run through the Orange County Housing Finance Trust). FHFC's FL Assist down-payment programs and HFA Preferred / HFA Advantage conventional loans apply to ADU-eligible primary residences but do not single out ADUs. Proposed CS/SB 1440 would create a state property-tax exemption of up to 100% of assessed value for an ADU rented at affordable rates.
State housing programs
Florida does not currently operate a statewide pre-approved ADU plan catalog (unlike California or Washington). State-level ADU implementation is driven by (a) the permissive § 163.31771 which lets willing jurisdictions adopt ordinances, (b) SHIP pass-through funding to local ADU programs (Orange County's Affordable ADU Loan Program is the model), and (c) the affordable-housing property-tax exemption under the Live Local Act (SB 102 / SB 328). The Department of Economic Opportunity (DEO) — now reorganized as the Department of Commerce — provides technical assistance to local governments but no statewide ADU-specific mandate or program. Major counties (Miami-Dade, Orange, Pasco, Hillsborough, Pinellas, Broward) have published their own ADU ordinances and guidance documents.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.