Adding a Guest Suite or ADU to Your Florida Home: What Homeowners and Investors Should Know

Every year around the holidays, Florida homes fill up. Grown kids come home, parents fly down for the winter, and friends from up north suddenly remember how much they miss you in January. For many homeowners, that's the moment the idea of a guest suite or backyard cottage stops being a someday project and starts being a real plan.

An accessory dwelling unit, or ADU, is a second, smaller home on the same lot as your main house. It might be a detached backyard cottage, an apartment over the garage, a converted garage, or an in-law suite addition attached to the home with its own entrance. ADUs give families room for aging parents and visiting relatives, and give investors a way to add a long-term rental to a property they already own.

Florida's ADU rules also got a lot of attention in Tallahassee this year. Here's what actually changed, what didn't, and what homeowners in St. Petersburg and Sarasota should know before planning one.

What Happened With Florida's ADU Bill in 2026

During the 2026 legislative session, lawmakers considered making ADUs much easier to build statewide. Senate Bill 48 would have required cities and counties to allow ADUs on single-family lots. The Florida Senate passed it unanimously in February, but the House never brought it to a final vote, and the bill died when the session ended in March.

Similar ADU language was also part of the House's broader housing bill, HB 1389, an update to the Live Local Act. The House and Senate disagreed over whether cities should be allowed to ban short-term rentals of ADUs, and the ADU provisions were dropped before the bill passed. HB 1389 was signed into law and took effect July 1, 2026, but it does not create a statewide right to build an ADU.

What this means for you: ADU rules in Florida are still set city by city and county by county. Whether you can build one, how big it can be, and how you can use it depends on your local zoning code, your lot, and, in many neighborhoods, your HOA. Lawmakers have signaled the issue will likely come back in a future session, but for now, your local rules are the ones that count.

St. Petersburg: One of Florida's More ADU-Friendly Cities

St. Petersburg has been expanding ADU eligibility for years. In 2022, City Council approved code changes that opened ADUs to more neighborhoods, and the city reports that about 70% of single-family lots now qualify. Under the city's current rules:

• Size: An ADU can be up to 800 square feet or 67% of the size of the existing home, whichever is less.

• Lot requirements: Eligibility depends on zoning. Neighborhood Traditional lots generally need at least 4,500 square feet, while Neighborhood Suburban lots need 10,000 square feet or an alley or corner location.

• Owner occupancy: The city does not require the owner to live on the property, which makes St. Pete especially attractive for investors.

• Parking: An additional parking space is generally required, though smaller units near frequent transit and alleys may qualify for a waiver.

• Rentals: Rentals in residential districts are long-term, with a 30-day minimum and only very limited exceptions. An ADU isn't a workaround for Airbnb or VRBO.

• Design: The ADU must match the architectural style of the main home, and separate utility meters and addresses are permitted.

The city offers an online ADU map lookup tool where you can enter your address to check eligibility, a useful first step before you spend money on design.

Sarasota County: Allowed, With an Owner on Site

Sarasota County adopted its ADU ordinance in 2019, allowing ADUs on single-family properties and removing an older rule that prohibited kitchens in accessory dwellings. Unlike St. Petersburg, the county requires the property owner to live on the property, either in the main home or the ADU. That makes Sarasota County ADUs a better fit for families housing a relative, or owners who want to live in one unit and rent the other, than for purely investment properties.

Rules differ between unincorporated Sarasota County and the City of Sarasota, and size limits, setbacks, and eligible zones vary, so confirm the specific requirements for your address with the right planning department before design begins.

Attached Suite, Garage Conversion, or Detached Cottage?

The right type of ADU depends on your lot, your budget, and how you plan to use it.

• In-law suite addition: An attached suite with its own bedroom, bathroom, and often a private entrance and kitchenette. Great for aging parents who want independence close to family, and often simpler for utility connections.

• Garage conversion: Uses an existing structure, which can reduce cost, but you'll need to account for replacing lost parking, raising or insulating the floor, and adding windows, plumbing, and HVAC.

• Detached backyard cottage: The most privacy for guests or tenants, and typically the strongest rental appeal, but usually the biggest investment in foundation, utilities, and site work.

• Garage apartment: A second-story unit over a new or existing garage. Height and story limits vary by zoning, so check local rules early.

Florida-Specific Factors That Affect Your ADU

A guest suite in Florida isn't just a smaller house. It has to meet the same codes and conditions as your main home, and a few issues come up again and again in coastal markets like St. Pete and Sarasota.

• Flood zones: In many waterfront and low-lying neighborhoods, new living space has to meet flood elevation requirements, and work on an existing home in a flood zone can trigger substantial improvement limits. Check your flood zone before you choose between an addition and a detached unit.

• Wind codes: Windows, doors, and roofing must meet Florida Building Code wind-load requirements, just like any new construction.

• Stormwater: St. Petersburg requires stormwater management, such as gutters and downspouts, for new ADUs.

• HOA restrictions: Even where local zoning allows ADUs, an HOA's deed restrictions can still prohibit them. Review your community's documents first.

• Utilities: Running water, sewer, and electrical to a detached unit can be one of the largest line items, especially on lots where the ADU sits far from existing connections.

  
  

Planning Now for Next Season

If the guest room is already feeling tight this holiday season, now is the right time to start planning, not building. Between zoning review, design, engineering, and permitting, an ADU is rarely a quick turnaround. Starting the process this fall puts you in a realistic position to have a finished suite ready for visitors next season, or a rental unit producing income sooner.

What This Means for Your ADU Project

• Florida did not pass a statewide ADU law in 2026, so local rules still decide what you can build

• In St. Petersburg, check your address with the city's ADU map lookup tool before you begin design

• In Sarasota County, plan on living on the property yourself, in either the main home or the ADU

• Plan on long-term rentals, not short-term vacation rentals, in most residential zones

• Review HOA restrictions, flood zone status, and utility access before choosing an ADU type

• Start planning in the fall to have a finished space ready for next season's guests

Whether you're making room for family or adding a rental to your property, an ADU starts with the right plan.

Maloney Construction helps Florida homeowners and investors plan and build in-law suite additions, garage conversions, and backyard guest homes, from early feasibility through permitting and construction. Contact our team to talk through your property and find out what's possible on your lot.

This article is intended for general informational purposes and reflects publicly available information as of October 2026. ADU regulations, zoning, flood requirements, and HOA rules vary by jurisdiction and property and may change. Confirm requirements with your local planning and building departments before starting a project.