The short answer: Florida has no statewide ADU mandate. Section 163.31771 of the Florida Statutes says a local government “may adopt an ordinance” to allow ADUs in areas zoned for single-family use, so each city and county decides. The statute also says a building permit application for an ADU must include an affidavit that the unit will be rented at an affordable rate to qualifying income groups. A 2026 bill to require ADUs statewide, SB 48, passed the Senate but died in the House.
Last verified: October 29, 2026 · Written by Marc
This guide summarizes section 163.31771 as published by the Florida Legislature on October 29, 2026. It is general information, not legal advice. ADU rules in Florida are local, so your city or county code decides what you can build.
Florida is one of the states owners most often ask about, and the answer surprises many of them: the state does not require cities to allow ADUs. Instead, it has a short statute from 2004 that lets local governments allow them and ties them to affordable housing. Whether you can build a backyard cottage in Miami, Tampa or Orlando depends on the local code. This guide explains what the state statute says, how to read its affordability language and how to check your own county or city.
What section 163.31771 says
The statute has five parts:
- Findings: the Legislature finds that home prices and rents have outpaced incomes in many urban areas, and that encouraging ADUs in single-family areas serves an important public purpose.
- Definitions: an ADU is “an ancillary or secondary living unit, that has a separate kitchen, bathroom, and sleeping area,” in the same structure as the primary home or on the same lot.
- Local option: a local government “may adopt an ordinance to allow accessory dwelling units in any area zoned for single-family residential use.”
- Affidavit: “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 extremely-low-, very-low-, low- or moderate-income persons.
- Housing element: each ADU allowed by an ordinance under the section counts toward the affordable housing component of the local comprehensive plan.
The section was created in 2004 and last amended in 2020, according to its history line.
What “may” means for owners
The key word is may. Florida’s statute permits local ordinances; it does not require them. That makes Florida very different from states such as California, Washington or Montana, where state law requires cities to allow at least one ADU.
| Question | Florida | States with a mandate (for example, California) |
|---|---|---|
| Must cities allow ADUs? | No: the local government may adopt an ordinance | Yes, at least one ADU on qualifying lots |
| Who sets size, setbacks, parking? | The local code | State floors, then the local code |
| Owner-occupancy rules | Local | Often barred by state law |
| Statewide approval deadline | None in the statute | Yes, for example 60 days in California |
The practical first step is to find out whose code applies. The statute’s “local government” means a county or a municipality, so a lot inside city limits follows the city’s ordinance, while a lot in an unincorporated area follows the county’s. Two neighbors on either side of a city line can face very different ADU rules, from a clear by-right path to no ADU ordinance at all. Our guide to ADU laws by state shows how unusual that patchwork is compared with states that set a statewide floor.
Common mistake: assuming a state law protects your ADU in Florida. Unless your city or county has adopted an ADU ordinance, the state statute does not give you a right to build one. Start with the local code.
Reading the affordability affidavit
As written, subsection (4) says a building permit application for an ADU “must include an affidavit” that the unit will be rented at an affordable rate to extremely-low-, very-low-, low- or moderate-income persons. The statute defines an affordable rental as one where rent plus utilities does not exceed 30 percent of the relevant income level.
How local governments apply that language varies, so do not assume either way. Two questions settle it for your project:
- Does your city or county ADU ordinance require the affidavit for every ADU permit, or only for units created under its section 163.31771 ordinance?
- If an affidavit is required, what rent limit and income group does the local government use, and for how long?
Ask the building or planning department in writing before you plan your rent. The answer can change the financial case for the unit as much as the construction cost does.
A hypothetical calculation shows what the affordability definition can mean. Suppose the income level that applies to a qualifying household in your county were $60,000 a year. Thirty percent of that is $18,000 a year, or $1,500 a month, and that amount would have to cover rent plus utilities. If you planned to charge $1,700 a month with utilities included, the unit would not meet that definition. The real income levels come from state law and your local government, so use their figures, not this example.
Practical tip: Request your local government’s ADU ordinance and its affidavit form together. Reading them side by side shows whether the affordability commitment applies to your unit, and what it would mean for the rent you planned.
The 2026 bill that did not pass
In 2026, Florida came close to a statewide rule. SB 48 would have required local governments to allow ADUs. It passed the Senate but died in House messages on March 13, 2026. As of October 29, 2026, section 163.31771 remains the state’s ADU law, and the local option stands.
If the Legislature takes up the issue again, the rules could change quickly. Check the Florida Senate’s bill pages before you rely on this guide for a project starting next year.
How to check your Florida lot
- Find your jurisdiction: city, or county if the lot is unincorporated.
- Search the local code for “accessory dwelling unit,” “guest house,” “garage apartment” or “in-law unit.”
- Read the ordinance’s standards: size, setbacks, height, parking and any owner-occupancy rule.
- Ask about the affidavit and any rent or income limits.
- Check flood zone and hurricane-related building requirements, which Florida building rules apply separately.
- Check HOA covenants, since Florida has no state ADU override for them.
- Get the answers in writing before you design.
Frequently asked questions
Does Florida require cities to allow ADUs?
No. Florida Statutes section 163.31771 says a local government may adopt an ordinance to allow ADUs in areas zoned for single-family use, so each city and county decides. A 2026 bill that would have required local governments to allow ADUs, SB 48, passed the Senate but died in the House on March 13, 2026.
What is the ADU affidavit in Florida?
Section 163.31771(4) says a building permit application for an ADU must include an affidavit that the unit will be rented at an affordable rate to extremely-low-, very-low-, low- or moderate-income persons, with rent and utilities at no more than 30 percent of the relevant income level. How local governments apply it varies, so ask your building department which permits require it.
How big can an ADU be in Florida?
The state statute does not set a size. It defines an ADU as a secondary unit with a separate kitchen, bathroom and sleeping area in the same structure as the main home or on the same lot, and leaves size, setbacks, height and parking to the local ordinance. Check your city or county code for its limits.
Can I rent an ADU on Airbnb in Florida?
It depends on your local rules and on any affidavit. If your permit included an affidavit to rent at an affordable rate to qualifying tenants, short-term rentals may conflict with it. Local short-term rental ordinances and HOA rules also apply. Ask your local government how its ADU ordinance and affidavit treat short-term rentals before you plan any.
Can my HOA block an ADU in Florida?
Florida’s ADU statute does not override private covenants, so an HOA’s rules can still restrict or prohibit ADUs. Read your declaration, bylaws and architectural guidelines before you design. Our guide to whether an HOA can block an ADU explains how states with HOA protections, such as California and Colorado, differ.
The bottom line
Florida ADU law leaves the decision to local governments: section 163.31771 says they may adopt an ordinance to allow ADUs in single-family areas, and it ties ADU permits to an affidavit for affordable rentals. There is no statewide mandate after SB 48 died in 2026, so your city or county code decides size, placement, parking and rentals.
Your next step is to find your local ADU ordinance and its affidavit form, then ask in writing how the affordability rule applies to your unit. Compare Florida with states that mandate ADUs in ADU laws by state.
Sources
General information, not legal advice. Local rules vary and change; confirm with your planning department.
Cover photo: “Craftsman bungalow, Old Northeast area of St Petersburg, FL 2020” by Calmuziclover, CC BY 2.0, cropped, via Wikimedia Commons.
Questions or a correction?
If something in this guide is unclear, out of date or does not match what your city told you, send me a message. Include the source if you have one.