StateDataIndex

ADU Guide · Verified 2026

Building an ADU in Florida

Depends on your city or county

Florida does not require cities and counties to allow ADUs. State law (Florida Statutes § 163.31771) is permissive, not mandatory — it encourages and authorizes local governments to adopt ADU ordinances to help with affordable housing, but does not force them to. So whether you can build an ADU depends entirely on your specific city or unincorporated county, your zoning district, and any HOA or deed restrictions. Two bills that would have created a statewide requirement (2025 and 2026) both failed.

Quick Facts

State rule
Permissive — § 163.31771 authorizes but does not require ADUs
Who decides
Your city or unincorporated county
2025 bill (SB 184)
Failed — did not become law
2026 bill (SB 48)
Died March 13, 2026 — did not become law
Owner-occupancy
Common — many counties require it (e.g., Clay County)
HOAs / deed rules
NOT preempted — recorded covenants can block an ADU
Flood zones
SFHA properties must build to Base Flood Elevation
Septic
Capacity is based on total bedrooms (main home + ADU)

Statewide floors set by Florida Statutes § 163.31771 (permissive statewide authorization). Your city may be more generous but cannot go below them.

The Three Types of ADU

Detached A standalone backyard unit. Allowed only where your local ordinance permits it — availability varies widely across Florida.
Attached Added onto the main home. Governed entirely by local rules, which differ city to city.
Interior conversion Converting part of the existing home. Subject to the same local-ordinance question and to Florida Building Code requirements.

The state law only encourages, it does not require

Florida Statutes § 163.31771 is the foundation of ADU regulation statewide, and its language is permissive: a local government "may adopt an ordinance to allow accessory dwelling units in an area zoned for single-family residential use." The legislature found that rising housing and rental costs created a shortage and that ADUs serve a public purpose — but it stopped at authorizing local governments to act, not requiring them to. As a result there is no statewide right; availability is a patchwork, and the local ordinance is the whole answer.

The statewide bills that failed

It is easy to find articles describing a coming statewide mandate — treat those with caution, because the bills they describe did not pass. SB 184 (2025) and SB 48 (2026) would have required every county and municipality to allow ADUs by right, capped local size limits, and restricted owner-occupancy rules — but SB 48 died on March 13, 2026, and neither became law. So the widely repeated provisions (a December 2026 deadline, a 1,000-square-foot floor, an owner-occupancy preemption) are NOT current Florida law. The controlling authority remains § 163.31771 plus your local ordinance.

How to find your actual rule

Because ADU rules are set locally, they vary widely across Florida cities and unincorporated counties. Start with your local planning or zoning department and confirm three things: whether ADUs are allowed in your zoning district at all, the size and setback limits that apply, and whether owner-occupancy is required. Many jurisdictions do require the owner to live on the property (Clay County, for example, requires occupying the main house), while others do not — this is one of the most variable points.

HOAs and deed restrictions can override zoning

Even where a city's zoning would allow an ADU, private HOA covenants and recorded deed restrictions are NOT preempted by Florida's ADU statute, and Florida courts consistently uphold properly recorded private deed restrictions over municipal zoning. If your HOA declaration prohibits accessory structures or additional dwelling units, you generally cannot build an ADU regardless of zoning. Pull your HOA documents from the county clerk's records and search for "accessory structure" and "additional dwelling unit" language before you invest in design.

Flood zones and septic add Florida-specific hurdles

Two physical constraints matter more in Florida than in most states. Properties in a Special Flood Hazard Area (zones A, AE, V, VE) must build the ADU to Base Flood Elevation, which adds engineering and cost. And septic capacity is calculated on the total bedroom count of the main house plus the ADU — adding an ADU can require a septic system upgrade, and you cannot build over a tank, leach field, or reserve field. Factor both in early if they apply to your lot.

Plans and permitting

Wherever ADUs are allowed, building one still means a building permit and compliance with the Florida Building Code. Many jurisdictions require construction plans prepared by a Florida-licensed professional engineer or registered architect, with site surveys and drainage studies — do-it-yourself plans are frequently not accepted. Plan for roughly 6 to 18 months from first inquiry to move-in, most of it in design, local review, and construction rather than the permit issuance itself.

What people get wrong

The most common error is believing Florida has passed a statewide ADU mandate. It has not — the bills that would have done that failed, and § 163.31771 remains permissive. The second error is assuming city zoning is the final word; a recorded HOA covenant or deed restriction can override it and block an ADU even where zoning allows one. Confirm both your local ordinance and your private covenants before planning.

From Idea to Move-In: The Timeline

Confirm local rules 1-2 weeks Whether ADUs are allowed is a local question — start with your city or county planning office.
Design & engineering 4-10 weeks Florida often requires licensed-engineer or architect plans, plus survey and drainage studies.
Permit & construction 6-14 months Includes Florida Building Code review; flood-zone or septic work adds time.
Final inspection 1-2 weeks Certificate of occupancy once inspections pass.

Building It Yourself? Here's What You'll Need

Planning an ADU? Tools homeowners use in the design and layout phase:

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Check Your Local Rules

Your city may allow more than the state floor

State law sets the minimum; many Florida cities are more generous. Confirm specifics with your local planning department.

Find your county building department →

Not sure if your project needs a building permit, a zoning approval, or both? See our guide to building permits vs. zoning approval.

Official Sources

ADU law changes frequently and local ordinances add detail. This guide is general information, not legal advice — always confirm with your local building department. Reviewed by the StateDataIndex Editorial Team · Updated August 2026.