Which St. Petersburg lots qualify?
As of October 2026, the city page sets eligibility by zoning:
- NT districts: a lot of at least 4,500 sq ft.
- NS districts: a lot of at least 10,000 sq ft, or one on an alley or a corner.
The city offers an ADU map look-up tool, and staff will confirm eligibility by email.
How big, and in what style?
The ADU may not exceed 800 sq ft or 67 percent of the existing home, whichever is less. It needs a bathroom and kitchen, an added parking space on the property, and must match the architectural style of the house. Modular buildings and shipping containers are allowed if they meet the design rules.
Do I have to live there?
No. The city says the main home does not need to be owner-occupied or homesteaded. If both units are rented, you need a Business Tax Certificate.
What about flooding?
The city notes that new buildings in flood zones must be elevated, and that remodeling in a flood zone is limited to 49 percent of the home's value. Gutters, rain leaders and an underdrain are typically required. We check the parcel's flood zone and the house value before choosing between a new structure and a conversion.
Is there any financial help?
In the South Side Community Redevelopment Area, the city's Affordable Residential Property Improvement Grant can reimburse up to 40 percent of eligible improvements, including ADU work, with income limits at 120 percent of area median income. The city describes eligibility rules in more than one place, so confirm the current terms with the program.
Conversion or new build in St. Pete?
It depends on the flood zone and the 49 percent limit. Converting part of a lower, older home in a flood zone can hit that limit quickly, while a new elevated cottage is judged on its own. We estimate the ratio before design.
Related
Rules as of October 2026. Source: City of St. Petersburg Accessory Dwelling Units page.
Find out what your St. Pete lot allows
Send the address. We check NT or NS eligibility and the flood zone.