Home › ADU Rules by County › St. Lucie County
How big a backyard home (accessory dwelling unit) can be in St. Lucie County, who can build one, and who to call to confirm — from the county's published rules.
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| ADUs allowed? | Yes, with conditions |
|---|---|
| Maximum ADU size | Not published in our records for the unincorporated county. Under Florida law, compliant ADU applications can't be capped below 1,000 sq ft. |
| Owner must live on site? | Not confirmed in our records |
| Manufactured home as an ADU? | Often allowed, subject to the county's ADU and zoning rules |
Confirmed: as of mid-2026 the UNINCORPORATED county's land development code does not yet reference ADUs (only ongoing discussion of 'accessible dwelling units'/tiny homes) — a conforming by-right ADU ordinance is required by Dec 1, 2026. City status varies: Fort Pierce permits ADUs (and under state law cannot require owner-occupancy or cap size below 1,000 sq ft), but Port St. Lucie's zoning code does not yet list ADUs as a permitted accessory use — see its municipality record. Check the address's jurisdiction first.
Source: St. Lucie County LDC + city rules; verified Jul 2026 — unincorporated county has no ADU ordinance yet, cities do.
Inside City Limits
If the property is inside city limits, the city's ADU rules apply instead of the county's.
Before You Build
ADU rules are set by each county and city — Florida law (Fla. Stat. 163.31771) lets local governments allow ADUs but doesn't require it — and they can change, so always confirm the current rule with St. Lucie County before you build.
Confirm with St. Lucie County: 772-462-1553 · zoning department website ↗
Zoning is set locally and changes often. Answers are guidance only, not a permit guarantee. Always confirm with the local building/zoning department before purchase.
Common Questions
Yes, with conditions. Confirmed: as of mid-2026 the UNINCORPORATED county's land development code does not yet reference ADUs (only ongoing discussion of 'accessible dwelling units'/tiny homes) — a conforming by-right ADU ordinance is required by Dec 1, 2026. City status varies: Fort Pierce permits ADUs (and under state law cannot require owner-occupancy or cap size below 1,000 sq ft), but Port St. Lucie's zoning code does not yet list ADUs as a permitted accessory use — see its municipality record. Check the address's jurisdiction first.
Not published in our records for the unincorporated county. Under Florida law, compliant ADU applications can't be capped below 1,000 sq ft.
Our records don't confirm an owner-occupancy requirement for St. Lucie County — ask the county zoning department before you buy.
Often yes — many Florida counties allow a manufactured or modular home as an accessory dwelling unit, subject to St. Lucie County's ADU size, lot, and setback rules. Confirm with the county for your parcel.
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