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ADU Rules in Miami, Florida

Complete guide to building an Accessory Dwelling Unit in Miami — zoning, setbacks, permits, costs, and more.

Max Size: 10% of lot area, up to 800 sq ft; the cap cannot be Waived (Art. 6 Table 13). Minimum sizes: 275 sq ft efficiency, 450 sq ft one-bedroom, 550 sq ft two-bedroom. A 5,000 sq ft lot therefore allows 500 sq ft; you need an 8,000 sq ft lot to reach 800 sq ft. Setbacks: 5 ft for a detached or one-story ancillary building (Illustration 5.3, Ancillary Building Setback). A two-story ADU attached to the house follows the principal rear setback of 20 ft (Sec. 3.18). Parking: Varies Verified: 2026-09-20

Researched by ADU Zoning Hub · verified 2026-09-20 against Miami planning code and Florida ADU law · methodology · 17 sources cited ↓

ADU Score: 6/10
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Are ADUs allowed in Miami, FL? [1][2][3][4]

Yes. Miami allows ADUs on most residential lots. A detached unit can be up to 800 sq ft, set 5 ft back from the rear line. Parking varies by lot and unit size. Owner-occupancy rules vary — confirm with the city. A building permit is required and applications are reviewed through the standard permit process.

Maximum size10% of lot area, up to 800 sq ft; the cap cannot be Waived (Art. 6 Table 13). Minimum sizes: 275 sq ft efficiency, 450 sq ft one-bedroom, 550 sq ft two-bedroom. A 5,000 sq ft lot therefore allows 500 sq ft; you need an 8,000 sq ft lot to reach 800 sq ft.
SetbacksRear 5 ft for a detached or one-story ancillary building (Illustration 5.3, Ancillary Building Setback). A two-story ADU attached to the house follows the principal rear setback of 20 ft (Sec. 3.18). · Side 5 ft per side for a detached or one-story ancillary building. A two-story attached ADU follows the principal side setback: 20% of lot width in aggregate, minimum 5 ft per side (Illustration 5.3).
Parking1 space per ADU (Art. 4 Table 4); none required inside a TOD or Transit Corridor. If the existing house leaves no room in the second or third layer, the space may go in the front layer on 2-ft-wide parking strips, exempt from driveway-separation and pervious-paving rules (Sec. 3.18).
Owner-occupancyHouse and ADU must be under the same ownership, and the ADU may be rented only while the property has current homestead status, so in practice the owner must live on site to rent it. The unit must be used predominantly as permanent housing and is subject to registration and annual renewal under the City Code (Sec. 3.18).

Do I need a permit to build an ADU in Miami? [5][6][7][8][9]

Yes. Every ADU in Miami needs a building permit. Review process: By right: building permit through the City of Miami Building Department (zoning review is part of the permit); no Warrant or hearing. A Waiver is needed only to adjust a setback by up to 10%. Register the ADU with the City and renew annually (Sec. 3.18)..

Permit feesAbout $2,200-$3,500 in city building fees on a $200,000-$350,000 unit: 0.50% of construction cost (min $110), $2.80 per $1,000 up-front, solid-waste $0.22 per $100 (max $600), energy $0.11/sq ft, CO $105 (Res. R-26-0200, 4/23/2026); zoning $250 up-front; impact fees extra.
Typical timelineNot published by the City. Florida Statute 553.792 gives the City 30 business days to review a complete residential application per cycle; plan on 3-6 months from submittal to permit including re-reviews and Miami-Dade County sign-offs.
Official Miami links:

Three things to know before you build in Miami

  • Look up your transect on the City's Miami 21 zoning atlas before anything else: ADUs need T3-L, T3-O or T4-T6. A T3-R lot cannot add one without a rezoning, and a duplex lot cannot add one at all (Art. 4 Table 3)
  • Size math is 10% of lot area: 5,000 sq ft lot = 500 sq ft; 7,500 sq ft = 750 sq ft; 8,000 sq ft or more = the 800 sq ft maximum. Attached or interior units stop at 500 sq ft, and the cap cannot be Waived (Art. 6 Table 13)
  • Rent only with homestead: the ADU may be rented only while the property carries a current homestead exemption, and the house and ADU must stay under one owner. If you move out, the rental has to stop (Sec. 3.18)

Last verified 2026-09-20 against Miami planning code. How we verify

The City of Miami allows one ancillary dwelling unit (ADU) by right on a lot with a single-family house in the T3-L, T3-O, T4, T5 and T6 transect zones, but not in T3-R, under Miami 21 Section 3.18 and Article 4 Table 3 as rewritten by Ordinance 14375 (Commission File 17018) in 2025. A detached ADU may be 10% of the lot area up to 800 sq ft (500 sq ft if it is inside or attached to the house), up to two stories but never taller than the house, with 5 ft side and rear setbacks for a one-story ancillary building and one parking space unless the lot is in a TOD or Transit Corridor. The house and ADU must stay under one owner, the unit may be rented only while the property has a current homestead exemption, and it must be registered with the City and renewed every year. You apply for a building permit with the City Building Department (0.50% of construction cost plus surcharges and impact fees); no zoning hearing is needed unless you ask for a Waiver. Addresses in unincorporated Miami-Dade County follow a different code (County Sec. 33-22, 7,500 sq ft lot minimum, annual Certificate of Use).

Zoning & Size Requirements [1][2][3][4]

Yes — Miami allows ADUs. A detached ADU can typically be up to 800 sq ft under current Florida and Miami zoning rules.

See what this means for your lot — ask Miami ADU builders for a quote →

Allowed ZonesBy right on a lot with a single-family residence in T3-L and T3-O (not T3-R) and in T4, T5 and T6 (Miami 21 Art. 4 Table 3; Sec. 3.18, Ord. 14375). Check your transect on the Miami 21 atlas: many single-family blocks are T3-R, where ADUs remain prohibited. Unincorporated Miami-Dade County uses its own rules (County Sec. 33-22: AU, EU, RU districts).
Max Size (Detached)10% of lot area, up to 800 sq ft; the cap cannot be Waived (Art. 6 Table 13). Minimum sizes: 275 sq ft efficiency, 450 sq ft one-bedroom, 550 sq ft two-bedroom. A 5,000 sq ft lot therefore allows 500 sq ft; you need an 8,000 sq ft lot to reach 800 sq ft.
Max Size (Attached)Inside or attached to the house: 10% of lot area, up to 500 sq ft (Art. 6 Table 13), same 275/450/550 sq ft minimums. A two-story attached ancillary building follows the principal-building setbacks (Sec. 3.18).
Max Size (JADU)No junior-ADU category. Converting rooms inside the house is simply an attached ADU (max 500 sq ft) and must contain its own sleeping/living area, bathroom and a kitchen with sink, food-prep counter and refrigerator (Sec. 3.18).
Max HeightAncillary buildings: 2 stories and 25 ft to top of slab or eave, and never taller than the house (Illustration 5.3). Second-story walls that abut a neighbor may have only clerestory windows no more than 24 in tall (Sec. 3.18).
Max Units1 ADU per lot, only on lots with a single-family residence (Art. 4 Table 3 footnote); it does not count toward density (Art. 1 definition). Not allowed with a duplex.

Setback Requirements [1][2][3][4]

Miami requires a rear setback of about 5 ft for a detached ADU, and parking requirements vary by unit size or location. Owner-occupancy is set by local rules (confirm with the city).

Rear Setback5 ft for a detached or one-story ancillary building (Illustration 5.3, Ancillary Building Setback). A two-story ADU attached to the house follows the principal rear setback of 20 ft (Sec. 3.18).
Side Setback5 ft per side for a detached or one-story ancillary building. A two-story attached ADU follows the principal side setback: 20% of lot width in aggregate, minimum 5 ft per side (Illustration 5.3).
Front Setback20 ft from the principal frontage and 10 ft from a secondary (corner) frontage for principal and ancillary buildings alike; a detached two-story ancillary building must also sit 10 ft from the house (Sec. 3.18, Illustration 5.3).
Parking Required1 space per ADU (Art. 4 Table 4); none required inside a TOD or Transit Corridor. If the existing house leaves no room in the second or third layer, the space may go in the front layer on 2-ft-wide parking strips, exempt from driveway-separation and pervious-paving rules (Sec. 3.18).
Owner OccupancyHouse and ADU must be under the same ownership, and the ADU may be rented only while the property has current homestead status, so in practice the owner must live on site to rent it. The unit must be used predominantly as permanent housing and is subject to registration and annual renewal under the City Code (Sec. 3.18).
Min Lot SizeT3 lots: 5,000 sq ft and 50 ft wide minimum (Illustration 5.3); no separate ADU lot minimum, but the 10%-of-lot cap means a 5,000 sq ft lot gets a 500 sq ft unit. Lot coverage 50% (first floor), 30% second floor in T3-L, green space 25%.

Permit Process & Fees [5][6][7][8][9]

An ADU permit in Miami goes through a standard permit review. Review time: not published by the City. Florida Statute 553.792 gives the City 30 business days to review a complete residential application per cycle; plan on 3-6 months from submittal to permit including re-reviews and Miami-Dade County sign-offs. Permit fees: About $2,200-$3,500 in city building fees on a $200,000-$350,000 unit: 0.50% of construction cost (min $110), $2.80 per $1,000 up-front, solid-waste $0.22 per $100 (max $600), energy $0.11/sq ft, CO $105 (Res. R-26-0200, 4/23/2026); zoning $250 up-front; impact fees extra.

Approval ProcessBy right: building permit through the City of Miami Building Department (zoning review is part of the permit); no Warrant or hearing. A Waiver is needed only to adjust a setback by up to 10%. Register the ADU with the City and renew annually (Sec. 3.18).
Review TimelineNot published by the City. Florida Statute 553.792 gives the City 30 business days to review a complete residential application per cycle; plan on 3-6 months from submittal to permit including re-reviews and Miami-Dade County sign-offs.
Permit FeesAbout $2,200-$3,500 in city building fees on a $200,000-$350,000 unit: 0.50% of construction cost (min $110), $2.80 per $1,000 up-front, solid-waste $0.22 per $100 (max $600), energy $0.11/sq ft, CO $105 (Res. R-26-0200, 4/23/2026); zoning $250 up-front; impact fees extra.
Impact FeesCity impact fees (City Code Ch. 13) plus Miami-Dade County mobility and school fees. The County's 2024-2027 rate sheet lists single-family detached at $9,275-$10,625 (mobility) plus $612 per unit and $0.918 per sq ft (school); the sheet has no ADU line, so request a written estimate before you design.
Plan CheckNot published; F.S. 553.792 sets a 30-business-day clock per review cycle, and re-reviews after the second cycle cost $56 per discipline
Pre-Approved PlansNo City of Miami program. Miami-Dade County's ADU Blueprint plans are pre-approved by the County Building Department for unincorporated-area permits; City of Miami permits are reviewed by the City's own Building Department.

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Construction Costs [10][11]

Building an ADU in Miami typically costs $150,000-$320,000 ($250-$450 per sq ft); a garage conversion runs $80,000-$160,000.

See what this means for your lot — ask Miami ADU builders for a quote →

Average Build Cost$150,000-$320,000
Cost per Sq Ft$250-$450
Garage Conversion$80,000-$160,000
Prefab ADU (Installed)$130,000-$250,000

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Rental Income Potential [12][13]

A 2-bedroom ADU in Miami rents for around $2,500-$3,000/mo, an estimated 6-8% net annual return.

Avg Rent (1 Bedroom)$2,100-$2,500/mo
Avg Rent (2 Bedroom)$2,500-$3,000/mo
Short-Term RentalNot permitted: Sec. 3.18 requires the ADU to be used predominantly as permanent housing, and it may be rented only while the property has homestead status
Est. Annual ROI6-8% net annual return

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Recent Law Changes

What's Changed Recently

  • Ordinance 14375 (Commission File 17018), shown on the City's official Miami 21 amendment log with an adoption date of October 1, 2025: rewrote the ADU rules into new Section 3.18, allowing ADUs by right on single-family lots in T3-L, T3-O, T4, T5 and T6 (T3-R stays excluded), setting the 800 sq ft detached / 500 sq ft attached caps (10% of lot area), homestead-only rental, one parking space (none in a TOD or Transit Corridor) and City registration with annual renewal. This is the ordinance our July 2026 page still described as having only passed first reading in February 2025
  • Ordinance 14484 (July 28, 2026) created Cottage Housing (Miami 21 Sec. 5.3.8): small single-family lots of 2,500-5,000 sq ft in T3-O inside a TOD or Transit Corridor, or existing T3 lots that already met those dimensions on May 1, 2026. It is a separate small-house type, not an ADU rule, and ADU standards are unchanged
  • Resolution R-26-0200 (April 23, 2026, with Ordinance 14456) adopted the current Building Department fee schedule (Exhibit C): residential permits at 0.50% of estimated construction cost, $110 minimum, $2.80 per $1,000 up-front fee, CO $105 per unit
  • Florida 2026 session: SB 48, which would have required every city and county to allow ADUs in single-family zones, passed the Senate but died in House messages on March 13, 2026; the housing bill that became law (HB 1389, Ch. 2026-179) contains no ADU provision. Fla. Stat. 163.31771 still says a local government "may" allow ADUs and was last amended in 2020, so Miami's own rules govern
  • Miami-Dade County's ADU Blueprint pre-approved plan program is live for unincorporated-county addresses (County Sec. 33-22: AU/EU/RU districts, 7,500 sq ft lot minimum, 400-800 sq ft, annual Certificate of Use, owner may not live in the ADU). It does not apply inside City of Miami limits

Tips for Building an ADU in Miami

  • Look up your transect on the City's Miami 21 zoning atlas before anything else: ADUs need T3-L, T3-O or T4-T6. A T3-R lot cannot add one without a rezoning, and a duplex lot cannot add one at all (Art. 4 Table 3)
  • Size math is 10% of lot area: 5,000 sq ft lot = 500 sq ft; 7,500 sq ft = 750 sq ft; 8,000 sq ft or more = the 800 sq ft maximum. Attached or interior units stop at 500 sq ft, and the cap cannot be Waived (Art. 6 Table 13)
  • Rent only with homestead: the ADU may be rented only while the property carries a current homestead exemption, and the house and ADU must stay under one owner. If you move out, the rental has to stop (Sec. 3.18)
  • A one-story detached ancillary building gets the 5 ft side and rear setbacks; go to two stories and a detached unit must be 10 ft from the house while an attached one follows the 20 ft principal setbacks (Sec. 3.18, Illustration 5.3)
  • Miami-Dade is a High-Velocity Hurricane Zone under the Florida Building Code and much of the city is in a flood zone: impact-rated openings, tie-downs and elevating the slab to base flood elevation plus freeboard (Miami 21 Art. 3) are the main reasons Miami ADUs cost more per sq ft than the Florida average
  • If your address is outside city limits (unincorporated Miami-Dade), a different code applies: County Sec. 33-22, AU/EU/RU districts, 7,500 sq ft minimum lot, 400-800 sq ft unit, annual Certificate of Use that only the owner can hold, and the owner may not live in the ADU
  • Cost basis (2026-09-20 re-verification, industry guides only): avg build cost $150,000-$320,000 all-in for a 450-800 sq ft detached unit (a Miami guide dated December 14, 2025 quotes $87,800-$224,800 for a 400-500 sq ft site-built unit including design, permit and utility connections, and modular from $129,000 with permits included); cost per sq ft $250-$450 turnkey; garage conversion $80,000-$160,000 and prefab $130,000-$250,000 are Florida guide ranges plus the Miami HVHZ premium, not Miami-specific quotes. Rents: Miami 1-bedroom median $2,450 (RentCafe, August 2026) to $2,500 (Zumper, September 19, 2026), studio $2,265; 2-bedroom $2,900-$2,995; ADUs in T3 neighborhoods usually let at or below these apartment medians

ADU Builders in Miami

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Sources & References

All data on this page is sourced from official government records and verified market data. View our full methodology.

  1. Miami 21 Code, Article 3 Sec. 3.18 Ancillary Dwelling Unit (ADU) Standards; Art. 4 Tables 3 and 4; Art. 5 Illustration 5.3; Art. 6 Table 13; Art. 1 definition (official codified host, CodeHub) Municipal Code — Accessed 2026-09-20
  2. View City of Miami Zoning Code (Miami 21) - City of Miami (links to CodeHub as the current code) Planning Department — Accessed 2026-09-20
  3. Accessory Dwelling Unit (ADU) - Miami-Dade County (unincorporated county rules, Sec. 33-22) Planning Department — Accessed 2026-09-19
  4. ADU Blueprint for Homeowners - Miami-Dade County Planning Department — Accessed 2026-09-19
  5. City of Miami Building Permit Fee Schedule (Exhibit C, Chapters 10, 17, 20; Res. R-26-0200, April 23, 2026) Planning Department — Accessed 2026-09-20
  6. Building Fee Schedule Exhibit C PDF - City of Miami Planning Department — Accessed 2026-09-20
  7. View Zoning Fees (City Code Sec. 62-22) - City of Miami Planning Department — Accessed 2026-09-20
  8. Impact Fees - Miami-Dade County Planning Department — Accessed 2026-09-20
  9. Miami-Dade County Impact Fees Rate Schedule (Dec 31, 2023 - Dec 30, 2027) Planning Department — Accessed 2026-09-20
  10. ADU Laws and Regulations in Miami, Florida (December 14, 2025) - Mesocore industry — Accessed 2026-09-20
  11. ADU Jacksonville FL 2026 (updated June 2026) - ADU Florida Info (Florida garage-conversion and prefab ranges) industry — Accessed 2026-09-20
  12. Miami, FL Rent Research (September 19, 2026) - Zumper Market Data — Accessed 2026-09-20
  13. Average Rent in Miami, FL (August 2026) - RentCafe Market Data — Accessed 2026-09-20
  14. Fla. Stat. 163.31771 Accessory dwelling units (2026 Florida Statutes) - Florida Legislature Government Data — Accessed 2026-09-20
  15. SB 48 (2026) Housing - bill history, died in House messages March 13, 2026 - Florida Senate Government Data — Accessed 2026-09-20
  16. CS/CS/HB 1389 (2026) Affordable Housing, enrolled text (Ch. 2026-179) - Florida Senate Government Data — Accessed 2026-09-20
  17. Florida Live Local Act (SB 102, 2023) - Florida Senate Government Data — Accessed 2026-09-19

Frequently Asked Questions

Can I build an ADU in Miami?

Yes. ADUs are allowed in By right on a lot with a single-family residence in T3-L and T3-O (not T3-R) and in T4, T5 and T6 (Miami 21 Art. 4 Table 3; Sec. 3.18, Ord. 14375). Check your transect on the Miami 21 atlas: many single-family blocks are T3-R, where ADUs remain prohibited. Unincorporated Miami-Dade County uses its own rules (County Sec. 33-22: AU, EU, RU districts). in Miami. The maximum size for a detached ADU is 10% of lot area, up to 800 sq ft; the cap cannot be Waived (Art. 6 Table 13). Minimum sizes: 275 sq ft efficiency, 450 sq ft one-bedroom, 550 sq ft two-bedroom. A 5,000 sq ft lot therefore allows 500 sq ft; you need an 8,000 sq ft lot to reach 800 sq ft.. Owner-occupancy: House and ADU must be under the same ownership, and the ADU may be rented only while the property has current homestead status, so in practice the owner must live on site to rent it. The unit must be used predominantly as permanent housing and is subject to registration and annual renewal under the City Code (Sec. 3.18).

How much does an ADU cost in Miami?

ADU construction in Miami typically costs $150,000-$320,000. Garage conversions run $80,000-$160,000, and prefab ADUs cost $130,000-$250,000.

How much can I rent an ADU for in Miami?

Average ADU rents in Miami are $2,100-$2,500/mo for a 1-bedroom and $2,500-$3,000/mo for a 2-bedroom unit.

Do I need parking for an ADU in Miami?

1 space per ADU (Art. 4 Table 4); none required inside a TOD or Transit Corridor. If the existing house leaves no room in the second or third layer, the space may go in the front layer on 2-ft-wide parking strips, exempt from driveway-separation and pervious-paving rules (Sec. 3.18).. Check with Miami planning department for the latest Florida ADU parking rules, as many states have relaxed requirements in recent years.

How long does it take to get an ADU permit in Miami?

Miami does not publish a standard ADU review timeline. Florida Statute 553.792 gives the City 30 business days to review a complete residential application per cycle; plan on 3-6 months from submittal to permit including re-reviews and Miami-Dade County sign-offs. Permit fees: About $2,200-$3,500 in city building fees on a $200,000-$350,000 unit: 0.50% of construction cost (min $110), $2.80 per $1,000 up-front, solid-waste $0.22 per $100 (max $600), energy $0.11/sq ft, CO $105 (Res. R-26-0200, 4/23/2026); zoning $250 up-front; impact fees extra.

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Miami ADU FAQ

Answers to every common question about building an ADU in Miami — costs, rules, permits, rental income.

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Miami ADU Costs

Detailed cost breakdown: construction $150,000-$320,000, garage conversion $80,000-$160,000, plus ROI analysis.

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Garage Conversion ADU Guide

Complete guide to costs ($80K-$180K), impact fee savings, and permits for garage-to-ADU conversions.

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Florida ADU Laws: SB 48 Update

Florida's SB 48 ADU mandate failed in the legislature. What this means for Miami homeowners now.

Read update →
About this information: This page is an informational summary of publicly available regulations - it is not legal, financial, or professional advice, and it is not a substitute for confirming requirements with your local planning department. Rules change frequently; always verify current requirements before designing, budgeting, or building. Last verified: 2026-09-20. Contractors we introduce are independent businesses - verify license and insurance directly before hiring. Spotted an error? Tell us - we verify against primary sources and correct quickly.

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