Miami, FL Accessory Structures: ADU Rules (2026)
ADU rules in Miami, FL, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Where allowed
- Single-family lots only
- Max height
- 2 stories (1 in T3-R)
- Detached 2-story separation
- 10 feet minimum
- Rental prerequisite
- Homestead exemption required
- Initial registration fee
- $300
Summary
Miami allows one ancillary dwelling unit on single-family lots under Miami 21 Section 3.18, capped at two stories (one in T3-R) and no taller than the main house, plus mandatory city registration.
An ADU, as defined in Article 1, titled 'Definitions', may be permitted in those Transect Zones pursuant to Article 4, Table 3, titled 'Building Function: Uses', on Lots containing a Single-Family Residence. ... Ancillary Buildings shall be limited to two (2) Stories, with the exception of those located in T3-R, which shall be limited to one (1) Story. Ancillary Buildings shall be no taller than the Principal Building.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 23 | Ordinance 11000 (Previous Zoning Code): Supplement 22 | Miami 21 (Zoning Code): ?).
Full Breakdown
An ADU is only permitted on a lot with a single-family residence, per the Transect Zones listed in Miami 21 Article 4, Table 3. It must stay under the same ownership as the principal house, and Ancillary Buildings are capped at two stories, just one story in T3-R, and can never be taller than the principal building. A detached two-story ADU needs a 10-foot separation from the main house; a one-story ADU follows the ordinary accessory-building setbacks. Before renting it out, the owner must separately register the unit with the city's office of zoning, which requires a building permit, certificate of occupancy, and proof of homestead exemption on the property.
Violations & Fines
Renting an unregistered ADU, or one that has lost its homestead-exemption backing, triggers denial or revocation of the ADU registration certificate and doubles the initial/annual registration fees under City Code Sec. 2-214(f)(3); violations also enforce through Chapter 2, Article X code-enforcement proceedings.
Frequently Asked Questions
Can I rent out a Miami ADU without registering it?
How tall can a Miami ADU be?
Sources & Official References
Other rules in Miami
How Miami compares: Easiest Cities to Build an ADU·Florida rules heatmap·Compare Miami to another location·View the Florida accessory structures overview
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ADU Rules in Nearby Cities
How other cities in Miami-Dade County handle adu rules.