Florida gives homeowners more flexibility to build accessory dwelling units than most people realize, especially since the state stepped in to limit how far local governments can restrict them. An accessory dwelling unit (ADU) is a secondary housing unit on the same lot as a primary residence, sometimes called a granny flat, in-law suite, backyard cottage, or carriage house. Landlords and homeowners build them to generate rental income, house family members, or increase property value. This guide covers everything you need to know before breaking ground in Florida.
How Florida defines an ADU
Under Florida Statute § 163.31771, an ADU is "an ancillary or secondary living unit that has a separate kitchen, bathroom, and sleeping area," located either within the same structure or on the same lot as the primary dwelling. That definition matters because it sets the legal floor for what local codes must allow. A unit meeting this description can't simply be prohibited because a municipality prefers it not exist.
ADUs go by several names across the state: in-law suites, granny flats, carriage houses, backyard cottages. The label doesn't change the legal category or how the unit is treated under state law.
What HB 1375 changed for Florida homeowners
Before House Bill 1375 took effect in 2023, local governments had wide latitude to restrict or effectively ban ADUs through zoning ordinances. That changed when the Florida legislature passed HB 1375, establishing statewide minimum allowances for ADUs and limiting how restrictive local rules can be. If a municipality had been blocking ADU construction through overly tight setback requirements or blanket prohibitions, those barriers are now harder to enforce.
The legislature's reasoning is worth understanding. Florida's median home prices have climbed well above what median incomes can support, and rental markets have tightened in nearly every metro area. ADUs add housing units quickly, on existing infrastructure, without requiring new land or large development projects. That's why the state decided local governments couldn't simply opt out of allowing them.
Types of ADUs allowed in Florida
Florida law doesn't limit homeowners to one style of ADU. The most common types include:
- Detached ADUs: standalone structures in the backyard or side yard, separate from the main home
- Attached ADUs: additions built onto the primary residence with a separate entrance
- Interior conversions: finished basement apartments, converted garages, or carved-out portions of the main house
- Manufactured homes: factory-built units placed on the lot as ADUs, permitted in many Florida counties
Manufactured homes are worth a closer look. Construction timelines are shorter than site-built units, upfront costs tend to be lower, and modern manufactured homes can be designed to match the primary residence. They're subject to the same local zoning and permitting requirements as any other ADU, so confirm with your county before purchasing a unit.
What local governments can and can't regulate
Local zoning still governs the specifics. Counties and cities can set requirements around setbacks, maximum square footage, height limits, parking, and design standards. What they can't do, post-HB 1375, is use those rules as a backdoor ban on ADUs in single-family residential zones.
In practice, requirements vary widely across the state. Miami-Dade, Broward, and Orange County each have their own ADU ordinances with different size limits and design standards. Before drawing up plans, contact your local planning or zoning department directly. That's the only source you should trust for current setback and size numbers, since those figures change.
For Broward County, check the Broward County Planning Services page. For Orange County, visit the Orange County Planning Division. Miami-Dade residents should consult the Miami-Dade Department of Regulatory and Economic Resources.
HOA restrictions still apply
One thing HB 1375 doesn't override: homeowners' association covenants. If you live in an HOA community, the association's CC&Rs may prohibit ADUs or impose conditions tighter than municipal code. Review your governing documents before spending money on plans. HOA rules are a private contract, and Florida's ADU legislation doesn't nullify them. This is one of the most common surprises for homeowners who assume state law clears the path entirely.
The permitting process
Building an ADU in Florida requires pulling permits through your local building department. You'll need to submit construction plans that meet Florida Building Code standards, including requirements for structural integrity, wind resistance, flood zone compliance, energy efficiency, and utility connections. Florida's hurricane exposure means structural and wind load requirements are particularly detailed, so working with a licensed architect or engineer familiar with local conditions is practical advice, not just a formality.
If you're building the ADU specifically as an affordable housing unit, Florida law requires submitting an affidavit as part of the permitting process affirming that commitment. Not every ADU triggers this requirement. Your local building department can tell you whether it applies to your project.
Working with a licensed contractor speeds up the permitting process considerably. You can verify a contractor's Florida license through the Florida Department of Business and Professional Regulation.
Owner-occupancy rules
Florida state law doesn't impose a blanket owner-occupancy requirement on ADU construction. However, some local ordinances do. Certain counties require the property owner to live in either the primary residence or the ADU, particularly for ADUs permitted under affordable housing programs. Check your local ordinance before assuming you can build an ADU as a pure investment property. Requirements in this area have been in flux as local governments update their codes following HB 1375.
Rental rules and short-term rentals
Renting out an ADU as a long-term rental is generally permitted where ADUs are allowed, subject to local landlord-tenant regulations. Short-term rentals (think Airbnb or VRBO) are a different matter. Florida has a complex relationship between state preemption and local short-term rental rules, and many municipalities restrict or regulate short-term rental activity separately from ADU regulations. If you're planning to use your ADU for short-term rentals, verify the rules with your local planning department and check whether any state licensing applies through the Florida Department of Business and Professional Regulation.
Costs to expect
ADU construction costs in Florida vary considerably by unit type, size, and location. A basic garage conversion might run $30,000 to $60,000. A new detached ADU typically ranges from $100,000 to $250,000 or more depending on size, finishes, and site conditions. Permit fees, utility connection costs, and impact fees add to that total and differ by jurisdiction. Some counties also charge school impact fees on new ADU construction, which can add several thousand dollars to the project cost.
Financing options include home equity loans, home equity lines of credit, and construction loans. Some lenders will also allow future rental income from the ADU to factor into loan qualification, which is worth discussing with a mortgage professional.
Protecting your investment with landlord insurance
If you plan to rent out your ADU, a standard homeowner's insurance policy almost certainly won't cover rental-related losses. Landlord insurance in Florida covers property damage, liability claims from tenants, and lost rental income when the unit becomes uninhabitable after a covered event. Getting coverage in place before a tenant moves in protects the financial return you built the ADU to generate in the first place.
Frequently asked questions
Does HB 1375 mean I can build an ADU anywhere in Florida?
Not exactly. HB 1375 requires local governments to allow ADUs in single-family residential zones, but local zoning still controls the specifics: setbacks, size, height, parking, and design standards. Check your county's current ordinance before assuming a project is automatically permitted.
Can my HOA block me from building an ADU even if county zoning allows it?
Yes. HB 1375 doesn't override private HOA covenants. If your CC&Rs prohibit ADUs or place conditions on them, those rules stand. Review your HOA documents before proceeding.
Is there a maximum size for ADUs in Florida?
Florida state law doesn't set a single statewide maximum. Size limits are set by local ordinances and vary by county and municipality. Some jurisdictions cap ADUs at a percentage of the main home's square footage; others use fixed square footage limits. Contact your local planning department for the applicable number in your area.
Can I use a manufactured home as an ADU in Florida?
In many counties, yes. Manufactured homes can qualify as ADUs if they meet local zoning and Florida Building Code requirements. Confirm with your specific county planning department, since some jurisdictions have additional restrictions on manufactured home placement.
What is Florida Statute § 163.31771?
Florida Statute § 163.31771 is the state law that defines ADUs and requires local governments to authorize them in residential zones. It establishes the affidavit process for affordable ADUs and limits how restrictive local ordinances can be. You can read the full text at the Florida Legislature's official site.
Do I need to live on the property to rent out an ADU?
It depends on your local ordinance. State law doesn't impose a universal owner-occupancy requirement, but some counties do. Check your local zoning code before purchasing a property specifically to build and rent an ADU without living there yourself.
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