Two homeowners on the same street can face completely different rules for the same backyard cottage if a city boundary runs between them. Accessory dwelling unit regulations in Tampa Bay are set locally, and the differences are not small: what you can build, how big, whether you can rent it, and how long approval takes all change at the jurisdiction line.

This guide compares the three rulebooks most of our clients encounter. Rules change, and every parcel has its own zoning and overlay details, so treat this as orientation, not a permit.

Key Takeaways

• Florida’s statute encourages ADUs but leaves the rules to cities and counties. A statewide bill is pending in Tallahassee this session, but nothing has changed yet.
• Tampa limits full ADUs to designated areas and treats everything else as a family-only Extended Family Residence.
• Unincorporated Hillsborough and St. Petersburg allow ADUs more broadly, each with its own size caps and conditions.

Where the State Stands

Florida Statute 163.31771 defines an accessory dwelling unit and allows local governments to adopt ordinances permitting them in single-family zones, particularly to expand affordable rental housing. It does not require any city to allow them.

In recent legislative sessions, bills have been introduced that would require every local government to allow ADUs by right in single-family zones and would limit owner-occupancy requirements. As this article is written, the 2026 version has cleared the Senate and is under consideration in the House. If it becomes law, local rules would change substantially. Until then, the local ordinance governs.

City of Tampa

Tampa draws a sharp line between two kinds of units:

Accessory Dwelling Units (ADUs) can be rented to anyone but are currently permitted only in specific zoning districts within designated areas, including Seminole Heights, the neighborhoods around Lowry Park, and the East Tampa and Tampa Heights overlay districts.

Extended Family Residences (EFRs) are permitted citywide but may be occupied only by an extended family member.

Requirement	Tampa ADU	Tampa EFR
Where allowed	Designated areas and districts only	Citywide
Who can live there	Anyone	Extended family only
Maximum size	950 sq ft of living space	600 sq ft
Owner-occupancy	Main residence must be owner-occupied	Main residence must be owner-occupied
Approval	Special Use with criteria and conditions	Special Use with criteria and conditions
Occupancy limit	Two occupants maximum	Family member(s)
Short-term rental	Not permitted; minimum one-week occupancy	Not applicable

Both types must include an independent kitchen (a microwave or hot plate can satisfy the cooking element), a bathroom, and a sleeping area. Detached units must meet accessory-structure setback and height rules, which vary by district and by unit size.

The city has held workshops in recent years about expanding ADU eligibility, and council members have signaled interest in broader areas. Check the city’s ADU page for current maps before assuming your neighborhood is in or out.

Unincorporated Hillsborough County

Outside city limits, in places like Carrollwood, Brandon, Riverview, and Lutz, the Hillsborough County Land Development Code applies. Its approach differs from Tampa’s:

• ADUs are allowed as an accessory use in most single-family and agricultural zoning districts, subject to conditions, rather than restricted to designated neighborhoods
• A minimum lot size applies (7,000 square feet in most cases)
• Living space is capped at around 900 square feet, with a variance path to a larger unit on larger lots
• One unit per lot, and the property owner must live in either the main house or the ADU
• Units above a detached garage are allowed only where the main house has two or more stories

Unlike Tampa, the county does not draw a distinction between family units and rentals, but it does require owner-occupancy on the property. As with the city, these rules have been the subject of recent review, and specifics can change.

City of St. Petersburg

St. Petersburg has been one of the more ADU-friendly cities in Florida, allowing units in several residential districts including the Neighborhood Traditional (NT) and Neighborhood Suburban (NS) districts, with design guidelines intended to keep new units compatible with the surrounding block.

Key standards:

• Maximum size of 800 square feet, and all area under roof may not exceed 67 percent of the main home’s floor area
• A minimum lot size, 4,500 square feet in the traditional districts
• Design requirements: the unit must match the architectural character of the main house, and second-story porches or stairs must orient toward the interior of the lot or meet a larger side setback
• Full kitchen and bathroom required; separate utility meters and a mailing address are permitted
• An additional on-site parking space is typically required

St. Petersburg publishes an ADU program page and fee schedule, and its Development Review staff will meet with homeowners before design begins.

Pinellas County and Other Cities

Unincorporated Pinellas, Clearwater, Largo, Temple Terrace, and Plant City each have their own ordinances. Some are more permissive than Tampa; some are more restrictive. The single most important step is to confirm which jurisdiction your parcel is in, then read that jurisdiction’s current ordinance.

Rules That Apply Everywhere

Regardless of jurisdiction:

• Homeowner association covenants are private and are not overridden by city or county zoning. If your HOA prohibits accessory structures, that controls.
• Flood zone requirements under the Florida Building Code apply to every new unit.
• Impact fees, utility connection fees, and permit fees vary widely and should be in your budget.
• Property taxes will be reassessed after construction. Some counties offer an assessment reduction for units housing a parent or grandparent age 62 or older.

Frequently Asked Questions

My house is in Tampa but not in one of the designated ADU areas. What can I build?

An Extended Family Residence for a family member, up to 600 square feet, with the main home owner-occupied. You cannot rent it to the general public under current rules.

Can I rent my ADU on a short-term platform?

Not in Tampa, where a minimum one-week occupancy applies to residential districts. Other jurisdictions have their own short-term rental rules; check before you plan around that income.

How do I find out which jurisdiction I’m in?

Your property tax bill lists the taxing authority. The Hillsborough or Pinellas County Property Appraiser’s website shows municipal boundaries. When in doubt, call the planning department and give them your address.

Is the pending state bill going to change all this?

Possibly. If enacted, it would require local governments to allow ADUs by right in single-family zones and would limit some local restrictions. It has not become law as this is written. Plan under current rules and stay informed.

Does an ADU count against my lot coverage?

Yes. Detached units and any new impervious surface count toward maximum lot coverage and impervious limits in every jurisdiction.

Where can I compare ADU costs?

Our ADU cost guide covers what drives the $175,000 to $350,000 range typical for a quality detached unit in Tampa Bay. Rules affect cost, too: size caps and design requirements shape what you can build.

Know the Rules Before You Design

A unit designed for the wrong rulebook is a costly restart. TomCo Solutions builds ADUs across Tampa Bay and begins every project by confirming jurisdiction, zoning, overlays, and flood zone for your specific parcel.

Schedule a private 30-minute consultation or call (813) 922-2299.