Building an ADU in St. Petersburg

Where you can build an ADU

Florida leaves ADUs to cities (see our Florida ADU law page). St. Petersburg expanded ADU eligibility "into more neighborhoods throughout the City" in July 2022, and its code was last amended for ADUs on July 10, 2025.

The code allows a new ADU only if:

• in NT (traditional neighborhood) districts, the lot is at least 4,500 square feet;
• in NS (suburban) districts, the lot is at least 10,000 square feet, or it is on an alley and at least 4,500 square feet, or it is a corner lot meeting the district's minimum area and width;
• in other districts, the lot meets the district minimum.

A detached ADU also needs a legal front and rear that match the other lots on the block face. No more than one ADU is allowed per single-family home, and it can't be built before the main house is started. [1][2][3]

Size, setbacks and design

Size. "The gross floor area of any accessory dwelling unit shall not exceed 800 square feet and all areas under roof may not exceed 67 percent of the floor area of the principal dwelling unit." For a detached ADU, that cap covers everything in the building, including storage and laundry, but excludes up to 300 square feet per required enclosed parking space (up to three).

Setbacks. A detached ADU in an NS district needs a 10-foot side setback, or 7.5 feet on an alley lot. An attached ADU follows the zoning district's setbacks. Second-floor porches or open staircases facing a neighbor's side yard need the district setback or 10 feet, whichever is greater.

Design. The building must "be compatible with the style of the building containing the principal use, including finishes, roof pitch, and paint scheme." An attached ADU's entrance must be on the side or rear and not visible from the street. A paved walkway at least 2 feet wide must link the ADU entrance to parking.

Modular buildings and shipping containers are allowed if they meet these design requirements. [1][2]

Parking

You must provide off-street parking for all uses on the site, and "At least one of the required parking spaces shall be an unobstructed space for exclusive use by occupants of the accessory dwelling unit." On an alley, the spaces go in the rear yard; without an alley, at the rear of the lot off a side street, and a driveway from the main street only if there is no other option.

The ADU parking requirement is waived only if all of these are true: the property is within 660 feet of a high-frequency transit route, the ADU is 600 square feet or less, it is on an alley, all the house's parking comes off the alley, and there is no front-loading driveway. [1]

Fees and timeline

The city's example for an 800-square-foot ADU with one bathroom is about $1,020 in fees:

• flat permit fee $187.50 plus $4.81 Florida surcharge;
• sewer impact fee $350 for one toilet;
• multi-modal impact fee (District 11) $419, assuming no credits;
• Certificate of Occupancy fee $56.25 plus $1.28 surcharge.

The city says plans are reviewed within 3-5 business days. Design, construction and utility costs are extra; see our ADU cost guide. [2]

Garage conversions

You can convert an attached front-facing garage into an ADU if you remove the garage door, make the new wall match the house, leave a 3-foot green strip between the wall and any remaining pavement, and keep the required parking entirely on your property. See our garage conversion guide. [1]

Renting it out

The city's FAQ says the main unit does not need to be owner-occupied or homesteaded, "but if both units are rental, a Business Tax Certificate is required." The program page's introduction still describes ADUs as something "owner-occupants" can create; the FAQ and code don't require owner occupancy.

Short-term rentals: the code says an ADU "shall not be utilized as a transient accommodation use." The city's FAQ adds that in residential districts you must rent for 30 days or more, and rentals under 30 days are allowed only 3 times in any 365-day period. Florida law also limits local vacation-rental rules adopted after June 1, 2011 (see our Florida ADU law page). Ask the city's ADU team (DevRev@stpete.org) how these rules apply to your ADU.

A lot with an ADU cannot be split to separate the ADU from the house unless the split meets all zoning and land development rules. [1][2][4]

Flood zones, HOAs and local help

In a flood zone, the city says "new buildings must be elevated, and remodeling is limited to 49% of the value of the home." FEMA treats improvements costing 50% or more of a building's market value as a substantial improvement.

The code says the ADU rules "do not override any deed restriction or homeowners' association declarations restricting accessory dwelling units, however the City has no authority to enforce such restrictions." Check your HOA rules.

If your property is in the South Side Community Redevelopment Area and your household income is below 120% of area median income, the Affordable Residential Property Improvement Grant can reimburse up to 40% of the pre-construction value of eligible ADU improvements or conversions. See the city's ADU page and our ADU financing guide. [1][2][5]

Permit steps in St. Petersburg

1. Check whether your lot qualifies

   Use the city's ADU Map Look-up or email your address to DevRev@stpete.org for verification. Corner lots in NS zones should be verified by email. [2]

2. Check your flood zone

   Look up your property on FEMA's Flood Map Service Center. In a flood zone, new buildings must be elevated and remodeling is limited to 49% of the home's value; email Floodplain@stpete.org with questions. [2]

3. Hire a contractor or qualify as an owner-builder

   A residential or general contractor is generally required unless the property owner will occupy the ADU and qualifies under the owner-builder option in Florida Statute 489. [2]

4. Prepare signed and sealed plans

   New structures need architectural or engineered plans with energy calculations and a site plan or survey. Follow the Residential Plan Review Checklist. Plans typically need gutters, rain leaders and an underdrain to send stormwater to the street. [2]

5. Submit through ePlan

   Apply for the building permit through the city's ePlan system; see Building Permits or email eplanreview@stpete.org. The city says plans are reviewed within 3-5 business days. [2]

6. Build, pass inspections and get a Certificate of Occupancy

   The ADU is permitted and inspected as an independent unit. The city's fee example includes a Certificate of Occupancy fee. [2]

Who to call

• ADU team, DevRev@stpete.org

  ADU eligibility, zoning and design questions; email to schedule a meeting with staff

  [2]

• Planning and Development Services, ePlan review

  Building permits and plan review (eplanreview@stpete.org)

  (727) 893-7230

  [2]

Questions people ask