Building an ADU in Florida

What Florida law says about ADUs

Florida's ADU law is Section 163.31771 of the Florida Statutes. It says: "A local government may adopt an ordinance to allow accessory dwelling units in any area zoned for single-family residential use." A "local government" means a county or a city. The word is "may", so a city or county can choose not to allow ADUs at all.

The law 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."

The Legislature's stated purpose is to encourage ADUs in single-family areas "to increase the availability of affordable rentals" for extremely-low, very-low, low and moderate-income people. ADUs allowed under such an ordinance count toward the affordable housing part of the local comprehensive plan. The 2026 statutes show the section was last amended in 2020. [1]

The affordable-rent affidavit

Subsection (4) of the law says: "An application for a building permit to construct an accessory dwelling unit must include an affidavit from the applicant which attests that the unit will be rented at an affordable rate to an extremely-low-income, very-low-income, low-income, or moderate-income person or persons."

"Affordable rental" means monthly rent and utilities of no more than 30% of the income limit for those groups. Cities handle this requirement in different ways, and their own ADU pages often don't mention it. Ask your city's permit office whether it requires the affidavit for your project and what it means for how you rent the unit.

The failed 2026 bill, SB 48, would have deleted this affidavit requirement. It is still law. [1][4]

The ADU bills that failed: SB 184 (2025) and SB 48 (2026)

SB 184 (2025) would have required local governments to allow ADUs. The Senate passed it 37-0 on April 9, 2025, and the House passed an amended version 97-10 on April 30, 2025. The Senate refused the House amendment, the House insisted on it, and the bill died in returning messages on June 16, 2025.

SB 48 (2026) passed the Senate 38-0 on February 4, 2026, and died in House messages on March 13, 2026. Its House companion, HB 313, died in committee. The Senate version would have required local governments (except those that state law requires to limit new housing units), by December 1, 2026, to adopt an ordinance letting ADUs in single-family zones be approved without a public hearing, variance or other discretionary action. That ordinance could not have:

• banned renting an ADU, except rentals shorter than one month;
• required the owner to live in the main house;
• added parking where the driveway has room for another car;
• required replacement parking when a garage or carport is converted;
• applied review standards that don't apply to other housing in the zone.

None of these limits are law. Your city's own code still decides. [2][3][4][5]

What passed in 2026: Live Local Act changes and a tiny-home study

The 2026 housing bill that did become law was HB 1389 (Chapter 2026-179), effective July 1, 2026. It amends the Live Local Act, which requires cities and counties to allow multifamily and mixed-use residential projects on land zoned commercial, industrial or mixed use when at least 40% of the units are rentals that stay affordable for at least 30 years. It does not deal with ADUs on single-family lots.

HB 1389 also directs the state's Office of Program Policy Analysis and Government Accountability (OPPAGA) to "evaluate the potential of tiny homes in meeting the need for affordable housing in this state" and report by December 31, 2027. See our tiny house guide for what is allowed now. [6][7]

Building code, hurricanes and flood zones

Every ADU in Florida is built to the Florida Building Code, a single statewide code that governs "the design, construction, erection, alteration, modification, repair, and demolition of public and private buildings." The 9th edition (2026) takes effect December 31, 2026. Miami-Dade County, for example, says all permit applications submitted on or after that date "must comply with the new edition." Ask your building department which edition applies to your plans.

If your lot is in a flood zone, federal flood rules matter. FEMA defines a "substantial improvement" as any addition or other improvement "the cost of which equals or exceeds 50 percent of the market value of the structure." Local rules can add limits. St. Petersburg, for example, says new buildings in the flood zone must be elevated and remodeling is limited to 49% of the home's value. Check your flood zone on FEMA's Flood Map Service Center. [8][9][10][11][12]

Short-term rentals and HOAs

State law limits how cities regulate vacation rentals: "A local law, ordinance, or regulation may not prohibit vacation rentals or regulate the duration or frequency of rental of vacation rentals." This does not apply to local rules adopted on or before June 1, 2011. Cities still set rules for ADUs themselves; Miami, for example, requires ADUs to be used as "predominately permanent housing," and Orlando limits home sharing to residents who live on site.

Homeowners' association rules are separate from city zoning. St. Petersburg's code says its ADU rules "do not override any deed restriction or homeowners' association declarations restricting accessory dwelling units," and Tampa says it does not review private deed restrictions. Read your covenants before you design. [13][14][15][16][17]

Where local rules differ

Because the state leaves ADUs to local governments, the rules vary a lot:

• Tampa allows ADUs only in certain neighborhoods, in most of them through a special use permit, up to 950 square feet.
• Orlando allows ADUs up to 500 or 1,000 square feet depending on zoning and lot size.
• St. Petersburg allows ADUs on qualifying lots in NT and NS zones and in other districts where its code allows them, up to 800 square feet.
• Miami expanded ADUs under its Miami 21 code in 2025 and requires a homestead exemption to rent one.

Our ADU permit process guide and ADU cost guide cover the general steps and budget. [14][16][18][19][20][21]

Florida laws to know

• Florida Statutes 163.31771, Accessory dwelling units

  Lets a county or city adopt an ordinance allowing ADUs in any single-family zone and requires an affordable-rent affidavit with the building permit application. [1]

• SB 48 (2026), proposed ADU mandate (did not pass)

  Would have required local governments to allow ADUs in single-family zones without a hearing by December 1, 2026; it passed the Senate 38-0 and died in the House. [3][4]

• SB 184 (2025), proposed ADU mandate (did not pass)

  A similar 2025 bill; the House passed an amended version, the chambers did not agree, and it died on June 16, 2025. [2]

• Florida Statutes 509.032(7), vacation rental preemption

  Bars local laws adopted after June 1, 2011 from banning vacation rentals or regulating how long or how often they are rented. [13]

• HB 1389 (2026), Chapter 2026-179 (Live Local Act changes)

  Amends the Live Local Act for multifamily and mixed-use projects and orders a state study of tiny homes for affordable housing, due by December 31, 2027. [6][7]

• Florida Statutes 553.73, Florida Building Code

  Creates the single statewide building code that covers the design and construction of every ADU. [8]

Questions people ask