Home › ADU Rules by County › Seminole County
How big a backyard home (accessory dwelling unit) can be in Seminole County, who can build one, and who to call to confirm — from the county's published rules.
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| ADUs allowed? | Yes |
|---|---|
| Maximum ADU size | 1,000 sq ft or 35% of the main home, whichever is less |
| Minimum lot size | 5,000 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 |
One ADU per single-family detached home, administratively approved in A-1, RC-1, single-family districts and single-family PDs. Lot must be at least 50 ft wide and 5,000 sq ft. One off-street parking space required (paved/stabilized, same driveway). Cities (Sanford, Altamonte Springs, Oviedo) set their own rules.
Source: Seminole County Land Development Code (Ord. 2021-13); verified Jul 2026.
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 Seminole County before you build.
Confirm with Seminole County: 407-665-7371 · 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. One ADU per single-family detached home, administratively approved in A-1, RC-1, single-family districts and single-family PDs. Lot must be at least 50 ft wide and 5,000 sq ft. One off-street parking space required (paved/stabilized, same driveway). Cities (Sanford, Altamonte Springs, Oviedo) set their own rules.
1,000 sq ft or 35% of the main home, whichever is less.
Our records don't confirm an owner-occupancy requirement for Seminole 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 Seminole County's ADU size, lot, and setback rules. Confirm with the county for your parcel.
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