City · Florida

ADU rules in Miami

3 sources

These are the primary sources for accessory dwelling unit regulations in Miami: the city's own zoning code, planning department pages, and permit guides. Start here before talking to anyone: the rules below are what your permit reviewer will apply.

Rules at a glance

Detached (backyard) ADU

Allowed

An ADU may be located in an Ancillary Building; a one story Ancillary Building may be attached or detached from the Principal Building, and a detached two story Ancillary Building must be separated from the Principal Building by at least ten feet and follow Ancillary Building setbacks. Only on lots containing a single-family residence, in transect zones where Art. 4 Table 3 permits the ADU use.

Miami 21 Code Sec. 3.18(d) (Placement); Art. 4 Table 3 (Ancillary Dwelling Unit row)

Attached or internal ADU

Allowed

An ADU may be within the Principal Building or in an attached Ancillary Building. A Principal Building containing an ADU must be designed visually as one single-family residence, the ADU must have a separate entrance, and that entrance may not face the street.

Miami 21 Code Sec. 3.18(d) (Placement) and 3.18(f) (Entrances and Elevations)

Maximum size

Detached ADU: ten percent of the lot area, up to 800 sq ft max. ADU within or attached to the principal building: ten percent of the lot area, up to 500 sq ft max. Minimum sizes: efficiency unit 275 sq ft, one bedroom 450 sq ft, two bedroom 550 sq ft. No waivers may be applied to maximum unit size.

These sizes appear in the T3 and T4 tables of Art. 6 Table 13; the T5 and T6 Table 13 tables contain no ADU row.

Miami 21 Code Art. 6, Table 13 (T3 Sub-Urban and T4 General Urban, Ancillary Dwelling Unit rows), referenced by Sec. 3.18(c)

Owner occupancy

Depends

The single-family residence and the ADU must always be under the same ownership. Owner occupancy in the form of a current homestead exemption (the property is the owner's primary residence under Florida law) is required only to rent the ADU, and is verified at initial registration and every annual renewal. If homestead status lapses, the owner must notify the office of zoning within 30 days.

Miami 21 Code Sec. 3.18(b) (Ownership and Use); City Code Sec. 2-214(a)(2)c, (a)(3)b, (b)

Extra parking

Minimum of 1 parking space per ADU; within a TOD (transit oriented development) or Transit Corridor no parking is required (per the T3 and T4 residential rows of Art. 4 Table 4). Where an existing legal principal building prevents the ADU space from being placed within the second or third layer, it may be placed in the first layer with exemptions from driveway separation and first layer paving rules, using parking strips no wider than two feet.

The ADU-specific parking line was verified in the T3 (Limited and Open) and T4 tables of Art. 4 Table 4; the T5 and T6 residential rows reviewed do not carry an ADU-specific line.

Miami 21 Code Art. 4, Table 4 (Density, Intensity and Parking, T3 and T4 Residential); Sec. 3.18(h) (Parking)

Approval process

Permitted use

Allowed By Right (designation R) in eligible transect zones under Art. 4 Table 3; a building permit, certificate of occupancy, and (before renting) an ADU registration certificate are required. A blank box in Table 3 means the use is prohibited, which is the case for T3-R. An amnesty program (City Code Sec. 10-77, $250 pre-submittal meeting) offers a legalization path for unpermitted ADUs.

Miami 21 Code Art. 4, Table 3 (Ancillary Dwelling Unit row and legend); City Code Secs. 2-214, 10-77

Rental restrictions

An ADU may only be rented if the property has current proof of homestead status. Before renting, the owner must obtain a building permit with a notarized ADU owner disclosure statement, a certificate of occupancy, and an ADU registration certificate from the office of zoning; the certificate must be renewed annually with a virtual or physical inspection (initial registration and inspection $300, annual renewal $250, re-inspections $75, doubled fees for unregistered operating ADUs). ADUs must be used as predominately permanent housing; renting as transient or temporary lodging is grounds for revocation.

Registration ordinance is City Code Ord. No. 14377, adopted 7-10-2025.

Miami 21 Code Sec. 3.18(b) (Ownership and Use); City Code Sec. 2-214 (Ancillary dwelling unit (ADU) compliance)

The fine print: 7 caveats that can change the picture

ADUs are permitted only on lots containing a single-family residence, and the residence and ADU must be under the same ownership (Art. 4 Table 3 footnote; Sec. 3.18(a)-(b)).
By right in T3-L, T3-O, and all T4, T5, and T6 subzones; prohibited in T3-R. Art. 4 Table 3 also marks the ADU use by right in CI-HD and D1.
The Art. 6 Table 13 minimum and maximum size rows exist only in the T3 and T4 tables; the T5 and T6 tables carry no ADU size row.
An ADU does not count toward maximum density calculations (Art. 1.1 definition).
Ancillary Buildings are limited to two stories, may be no taller than the Principal Building, and a detached two story Ancillary Building needs a minimum ten foot separation from the Principal Building (Sec. 3.18(d)-(e)).
Coconut Grove NCD-3 (Appendix A) modifies T3 regulations, including Ancillary Building setbacks; in its single family provisions an Ancillary Building may not be used as or converted to an ADU without a recorded Declaration of Restriction.
Renting an ADU requires homestead exemption plus an ADU registration certificate renewed annually with inspection; homestead lapses must be reported within 30 days (City Code Sec. 2-214).

Summarized from Miami's ordinance text, read July 2026; every row links the code section it came from. Rules often vary by zone and lot, so treat this as orientation, not a permit determination, and confirm with the planning department before you commit to a design.

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ADU regulations

Florida statewide law also applies

Florida sets baseline ADU rights at the state level. Where local rules are stricter than state law allows, state law usually wins, so both are worth reading.

See Florida statewide rules

Spotted something outdated?

Zoning codes change. If a link is dead or Miami has updated its ordinance, report it and we'll verify against the official source.

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