How big can an ADU be in Jacksonville?

As reported on Ordinance 2022-0448, the footprint is limited to 25% of the main home's gross floor area or 750 sq ft, whichever is less, and the ADU cannot be taller than the main house.

Does Jacksonville's ADU ordinance apply to Jacksonville Beach?

No. Reporting on the 2022 ordinance noted it does not apply to the Beaches or to Baldwin, which keep their own rules.

Did Florida pass a law requiring ADUs in 2026?

No. SB 48 (2026) passed the Florida Senate 38 to 0 on February 4, 2026, but died in House messages on March 13, 2026.

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Are ADUs allowed in Jacksonville?

Updated October 2026

Yes, on most low-density residential lots. Since Ordinance 2022-0448 took effect, the City of Jacksonville allows one ADU per lot as a permitted use, behind the main house and no taller than it, with the owner living on the property. It depends on your HOA and location: the ordinance does not override an HOA ban and does not cover the Beaches or Baldwin.

What did the 2022 ordinance change?

The City Council passed two measures on November 9, 2022: Ordinance 2022-0447, amending the comprehensive plan, and Ordinance 2022-0448, amending the zoning code, the latter by a 12 to 7 vote. Together they let ADUs be built as an accessory use on conforming residential lots in the agriculture, rural residential, low-density residential, medium-density residential and residential-professional-institutional land use categories.

What are the main limits?

One ADU per conforming residential lot.
Built behind the main house, with a visual relationship to it.
No taller than the main house.
A footprint of no more than 25% of the main home's gross floor area or 750 sq ft, whichever is less.
The homeowner must live on the property.

These points come from reporting on the ordinance when it passed. Code wording and later amendments can refine them, so we read the current text for your lot.

Small backyard home (ADU): Black 2-storey house under white clouds

Where does it not apply?

The Beaches and Baldwin. Jacksonville Beach, Neptune Beach, Atlantic Beach and Baldwin keep their own rules. See ADUs in Jacksonville Beach.
HOA communities that ban ADUs. See can an HOA block an ADU.
Nonconforming lots. The use is tied to conforming residential lots.

Does Florida law require Jacksonville to allow ADUs?

No. Florida Statute 163.31771 lets local governments adopt ADU ordinances but does not require them. A 2026 Senate bill that would have required it, SB 48, passed the Senate 38 to 0 and died in the House in March 2026. Jacksonville's rules come from its own ordinance.

When is the answer no?

It depends on three things: an HOA covenant against second units, a lot outside the ordinance's area, or a site where the flood zone, septic field or setbacks leave no legal footprint. Send the address and we will tell you which, if any, applies.

Check what your lot allows

Share the address and your idea. We find out which government issues the permit, then check zoning, flood zone, covenants and setbacks, and tell you which ADU types are realistic.

Serving Jacksonville, Jacksonville Beach, Orange Park, St. Augustine and Fernandina Beach.