Accessory Dwelling Units in Florida: SB 48, Zoning, and Permits

Accessory dwelling units are permitted on single-family residential lots in Florida under Section 163.31771 of the Florida Statutes, which authorizes local governments to allow them in single-family zones.¹ Whether you can actually build one today depends on your city or county, but that patchwork is about to shrink: pending 2026 legislation (SB 48) would require every county and municipality to adopt an ADU-friendly ordinance by December 1, 2026.² Before breaking ground, you still have to work through zoning, permits, building codes, property tax consequences, rental rules, insurance, and any HOA restrictions.

What SB 48 Would Change

SB 48 advanced through multiple committees in the 2026 legislative session with provisions that would rewrite ADU regulation across the state. It would require every county and municipality to adopt an ordinance allowing ADUs by December 1, 2026, without a public hearing, variance, conditional use permit, or special exception. Homeowners would only need to show that their site plan conforms with applicable zoning rules.²

Under the bill, local governments could not:

Ban ADU rentals, though they could still restrict short-term rentals under one month.
Require the property owner to live in the primary dwelling.
Impose additional parking requirements when the driveway can fit another vehicle without blocking access to the main home.
Require replacement covered parking when a garage or carport is converted into an ADU.
Apply conditional use approvals, special exceptions, or other review standards not applied to other housing in the same zone.

The bill would also remove the current requirement that owners attest the ADU will be rented at an affordable rate to low-income tenants, while still letting affordable ADUs count toward local comprehensive plan housing goals.² Check the bill’s status before you plan around it. Until SB 48 is signed and takes effect, current local rules control.

Local Zoning Rules Still Set the Envelope

Even with the statewide framework, local governments decide setbacks, lot size minimums, height restrictions, and maximum square footage. Tampa publishes lot size and dimensional standards specific to ADUs.³ Sarasota County allows ADUs under its use table but requires them to follow accessory structure placement rules that generally keep them out of required setback areas.⁴

Most jurisdictions treat attached and detached ADUs differently. Attached units, such as garage conversions or additions built onto the main home, share the existing footprint and often face fewer hurdles. Detached units usually have to sit behind the primary residence and meet stricter setback and impervious surface limits.

What Counts as an ADU

An ADU is a separate living space with its own kitchen, bathroom, and sleeping area. The kitchen part is looser than people expect. In Tampa, a “cooking element” is all that’s needed to qualify, which can be as simple as a microwave or hot plate.⁵ Definitions vary across jurisdictions, so read your local code before you finalize the layout. Adding a full kitchen to a space that previously lacked one can reclassify it and trigger additional permitting.

Short-Term Rentals

Some municipalities restrict or prohibit ADU use as short-term vacation rentals. Miami Beach and Orlando require short-term rental properties to register and follow vacation rental regulations. If SB 48 becomes law, local governments could still prohibit ADU rentals for terms under one month, so short-term rental restrictions would survive.²

Permits, Inspections, and Utilities

Every ADU in Florida needs a building permit from the local building department. The application requires a site plan and floor plan showing zoning setbacks, lot coverage, and building code compliance. Many jurisdictions encourage or require a pre-application meeting, which is worth taking because it catches problems before you spend money on construction drawings.

After submission, the building department reviews plans for zoning, structural, environmental, and utility compliance. Orlando and Miami run digital permitting systems that move applications faster. Revisions and resubmittals can add weeks, so accurate initial plans matter. Permit fees vary by jurisdiction and typically include plan review fees, impact fees, and utility connection charges, with total permitting costs running from about $1,000 to several thousand dollars depending on county, ADU size, and whether new utility connections are needed. Inspections occur at multiple stages: foundation, framing, plumbing, electrical, and final occupancy.

Shared Versus Separate Utilities

You’ll need to decide whether the ADU shares utilities with the main home or gets separate meters. In Largo, a property with one water meter receives a single bill covering both the primary home and the ADU; separate meters mean separate bills. Whether a separate connection is required depends on factors like elevation differences and sewer line routing, which the city evaluates during permitting.⁶

Shared utilities cost less up front and work well when a family member will occupy the ADU. Separate meters make more sense for rentals because you can bill the tenant directly and create a cleaner record for tax purposes. Separate connections can also affect how the property appraiser classifies the ADU.

Building Code Standards

ADUs have to meet the Florida Building Code, which applies the same structural, electrical, plumbing, and energy standards as any primary residence. The code is updated on a three-year cycle, and recent editions have tightened wind and flood requirements.

Hurricane and Flood Requirements

In Miami-Dade and Broward Counties, residential construction sits within the High-Velocity Hurricane Zone, where design wind speeds for standard residential structures reach 180 mph or higher under current engineering standards.⁷ HVHZ construction requires impact-resistant windows, reinforced roofing, and structural connections built to keep the envelope intact in a major hurricane. These rules apply to ADUs the same as any other dwelling.

ADUs in flood-prone areas also have to meet FEMA elevation requirements, which can mean elevated foundations or pilings. Flood zone classification drives both construction cost and insurance premiums, so confirm your zone early.

Energy and Electrical

The Florida Energy Conservation Code sets insulation, lighting, and HVAC efficiency standards, and the unit needs high-efficiency water heating and proper insulation to pass inspection.⁸ Electrical work follows the National Electrical Code, including ground-fault circuit interrupters in kitchens, bathrooms, garages, and outdoor areas.

Property Tax and Homestead Impact

Building an ADU raises your property’s assessed value. Florida law requires county property appraisers to reassess when improvements are made, and new construction is valued at market rate in the year it’s built. That added value increases your tax bill according to local millage rates.

Florida’s Save Our Homes cap normally limits annual assessment increases on homesteaded property to 3% or the change in the Consumer Price Index, whichever is less. New construction like an ADU is assessed at full market value when built, then capped the following year.⁵

Renting the ADU complicates things. Tampa’s property appraiser evaluates whether the ADU is used for rental purposes during permitting, and a rented ADU is assessed separately as non-homestead property that does not qualify for the Save Our Homes cap. SB 48 reinforces this statewide: an ADU won’t disqualify the owner’s homestead exemption on the main residence, but a rented ADU must be assessed and taxed separately according to its use.² Talk to your county property appraiser before construction so the numbers don’t surprise you.

Renting Out the ADU

Renting an ADU triggers the Florida Residential Landlord and Tenant Act, which governs lease agreements, maintenance, eviction procedures, and tenant protections.⁹

Security Deposits

If you collect a security deposit, Florida law requires written notice to the tenant within 30 days disclosing how and where the deposit is held. If you hold it in an interest-bearing account, you owe the tenant interest. If you post a surety bond instead, you must pay 5% annual simple interest to the tenant.¹⁰ Skipping these steps can cost you the right to make a claim against the deposit when the tenant moves out.

Fair Housing and Occupancy

Federal fair housing law prohibits discrimination based on race, color, religion, sex, national origin, disability, and familial status. ADU owners run into trouble on familial status when they set tight occupancy limits. HUD guidance uses a square-footage standard rather than a straight bedroom count: at least 150 square feet for the first occupant and 100 square feet for each additional person, with sleeping rooms needing at least 70 square feet for one person and 50 square feet per person in shared rooms. Limits stricter than these can support a disparate impact complaint.

Some Florida cities also require landlords to register rental units and pay an annual licensing fee, with fines or loss of rental rights for noncompliance.

Insurance Gaps to Fix Before You Build

Standard homeowners policies cover detached structures under “other structures” coverage, usually capped at 10% of your dwelling coverage limit. On a home insured at $300,000, that means only $30,000 for a detached ADU, which won’t be enough if you’ve spent $100,000 or more building it. Contact your insurer to raise the limit before the unit is finished.

Renting shifts the picture again. Most homeowners policies assume owner-occupied structures. Once a tenant moves in, your insurer may treat the ADU as a separate risk and decline coverage for guest injuries, tenant-caused damage, or lost rental income. Short-term rentals are especially problematic because insurers often classify that activity as a business excluded from residential coverage. Ask about a short-term rental endorsement for occasional use or a separate dwelling fire policy for full-time rentals.

Unpermitted ADUs are the worst-case exposure: insurers routinely deny claims for damage tied to work that was never inspected or approved. An electrical fire in a unit with substandard wiring can leave the homeowner personally liable for the full cost of damages and any tenant injuries.

HOA and Community Association Rules

If your property sits in a community governed by a homeowners’ or condominium association, those private rules apply on top of local zoning and can be stricter. Florida courts have generally upheld an association’s authority to regulate property use and to amend restrictions even when the change affects current owners. Many HOAs prohibit ADUs outright or impose architectural guidelines on size, materials, and placement.

Where an HOA does allow ADUs, the board may require prior approval or restrict who can occupy the unit. Violations can bring fines, legal action, or an order to remove the structure. Read your community’s declaration of covenants, bylaws, and architectural review standards before you spend on design or permitting, and get any board approval in writing.

Financing

ADU construction typically runs $150 to $400 per square foot depending on attached versus detached, level of finish, and local material and labor costs. Several federal lending programs recognize ADUs and let projected rental income help borrowers qualify.

FHA

Under FHA Mortgagee Letter 2023-17, borrowers can use ADU rental income to help qualify for an FHA-insured mortgage. On a property with an existing ADU, lenders can count 75% of estimated rental income. For a new ADU built through the FHA’s Standard 203(k) Rehabilitation program, that drops to 50%. In both cases, the ADU rental income used for qualification can’t exceed 30% of the borrower’s total monthly effective income.¹¹

Conventional

Fannie Mae’s HomeStyle Renovation loan covers ADU construction with loan-to-value ratios up to 97% on primary residences.¹² Freddie Mac’s CHOICERenovation mortgage takes a similar approach, permitting one ADU on properties with one to three units and requiring compliance with local zoning, with an exception for certain one-unit properties where the ADU doesn’t conform.¹³

Federal Income Tax on ADU Rent

Rental income from an ADU is taxable and reported on Schedule E of your federal return. You can deduct expenses tied to the rental, including allocated portions of property taxes, insurance, maintenance, and utilities. The IRS requires residential rental property to be depreciated over 27.5 years on a straight-line basis, and depreciation starts when the unit is ready and available for rent. Only the building and structural components depreciate; land does not. If you converted an existing space into a rental ADU, your depreciation basis is the lesser of the property’s fair market value or your adjusted basis on the date of conversion.¹⁴

What Skipping Permits Costs

Building or renting an ADU without proper permits gets expensive quickly. Local code enforcement issues citations for zoning, permitting, and building code violations, and daily fines accumulate until the problem is resolved. In Fort Lauderdale, a special magistrate can impose fines of up to $500 per day for unresolved code violations.¹⁵ Other municipalities enforce similar structures. Unpaid fines become liens on the property, blocking any sale or refinance until cleared.

The exposure runs past fines. An unpermitted ADU that catches fire or injures a tenant is a liability problem. Insurance companies routinely deny claims tied to unpermitted construction, leaving the homeowner personally responsible for damage and injury costs. A tenant hurt in a unit with defective wiring or no fire egress has strong grounds for a negligence suit. Retroactively permitting and bringing a unit into compliance almost always costs less than the combined risk of fines, denied claims, and personal liability.

1
Florida Senate. Florida Code Title XI Chapter 163 – Accessory Dwelling Units
2
Florida Senate. CS/CS/SB 48 Bill Analysis – Accessory Dwelling Units
3
City of Tampa. ADU General Standards
4
Sarasota County Code of Ordinances. Section 5.4 – Accessory Uses and Structures
5
City of Tampa. Accessory Dwelling Units and Extended Family Residences FAQs
6
City of Largo. Accessory Dwelling Units
7
Florida Building Commission. ASCE 7-16 Fact Sheet – Wind Loads
8
Building Energy Codes Program. Florida Energy Code Status
9
The Florida Legislature. Florida Statutes Title VI Chapter 83 – Landlord and Tenant
10
The Florida Legislature. Florida Statutes 83.49 – Deposit Money or Advance Rent
11
U.S. Department of Housing and Urban Development. Mortgagee Letter 2023-17 – Revisions to Rental Income Policies and Property Eligibility
12
Fannie Mae. HomeStyle Renovation
13
Freddie Mac Single-Family. Accessory Dwelling Units
14
Internal Revenue Service. Publication 527 – Residential Rental Property
15
City of Fort Lauderdale. Community Enhancement and Compliance Hearings