Home › ADU Rules by County › Miami-Dade County
How big a backyard home (accessory dwelling unit) can be in Miami-Dade 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 | 400–800 sq ft (RU-1 districts) |
| Minimum lot size | 7,500 sq ft |
| Owner must live on site? | Yes — in the main home or the ADU |
| Manufactured home as an ADU? | Often allowed, subject to the county's ADU and zoning rules |
Allowed in AU, EU, RU and GU zones within the Urban Development Boundary via a Certificate of Use (renewed annually). Owner must live in the primary home or the ADU as principal residence; only the owner may obtain the CU. One ADU per lot; may be rented (min 30 days). County is in the High-Velocity Hurricane Zone — strictest construction standards. 30+ municipalities set their own rules.
Source: Miami-Dade County code / county ADU page; verified Jul 2026.
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 Miami-Dade County before you build.
Confirm with Miami-Dade County: 305-375-2800 · 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. Allowed in AU, EU, RU and GU zones within the Urban Development Boundary via a Certificate of Use (renewed annually). Owner must live in the primary home or the ADU as principal residence; only the owner may obtain the CU. One ADU per lot; may be rented (min 30 days). County is in the High-Velocity Hurricane Zone — strictest construction standards. 30+ municipalities set their own rules.
400–800 sq ft (RU-1 districts).
Yes. Miami-Dade County requires the owner to live on the property, in either the main home or the ADU.
Often yes — many Florida counties allow a manufactured or modular home as an accessory dwelling unit, subject to Miami-Dade County's ADU size, lot, and setback rules. Confirm with the county for your parcel.
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