Can I Build ADU in Miami, FL? (2026)
Find out if you can build a adu in Miami, FL. Rules, permit requirements, costs, and next steps.
Yes, ADUs are allowed in Miami, FL. California state law ensures by-right approval.
An Accessory Dwelling Unit (ADU) is a secondary housing unit on a residential lot — also called a granny flat, in-law suite, or backyard cottage. In Miami, FL, ADUs are permitted by right under state law, making them one of the most accessible ways to add housing on your property. ADUs can be detached, attached to the main home, or created by converting an existing garage or accessory structure.
ADU Rules in Miami
ADU Rules in Miami: Detached ADU max size: 750 sqft or 50% of primary structure, whichever is less. Attached ADU max size: 50% of primary structure square footage. Setbacks: 5 ft side, 5 ft rear. Owner-occupancy: Owner-occupancy requirement eliminated statewide effective July 1, 2024 per Florida HB 1339. Neither primary dwelling nor ADU must be owner-occupied.. State preemption applies: FL law requires Miami to approve compliant ADUs by right.
Costs & Fees
ADU permits in Miami: Total estimated permit cost: $5,000–$15,000 total permit fees depending on size and scope. Contact the City of Miami Building Department for current fee schedule.
Timeline
Ministerial approval required per Florida HB 1339 — no discretionary review for ADUs meeting objective standards. Miami Building Department typically processes ADU permits in 4-8 weeks for plan check. Construction typically 4-12 months.
Next Steps
Next steps for building an ADU in Miami: 1. Review full ADU rules including size limits, setbacks, and parking. 2. Apply for an ADU permit through the City of Miami Building Department at https://epermits.miamigov.com/. 3. Hire a licensed contractor familiar with FL ADU requirements.
City of Miami Building Department
Phone: (305) 416-1100
Website: https://www.miamigov.com/Government/Departments-Organizations/Building
Online Permits: https://epermits.miamigov.com/
Frequently Asked Questions
Can I build an ADU (Carriage House) on my Miami property?
Yes. Florida HB 1339 (2024) requires Miami to permit ADUs by-right without owner-occupancy requirements. In T3 (Sub-Urban) zones — Miami's primary single-family transect — you can build a Carriage House in the rear of your lot. Miami 21 regulates size, height, and setbacks. Impact fees are capped by state law. The permit process is ministerial (no discretionary review) for ADUs meeting objective standards.
What zoning system does Miami use?
Miami uses a form-based code called Miami 21, adopted in 2009. Instead of traditional use-based zoning, Miami 21 organizes the city into Transect Zones based on urban character — from T1 (Natural) through T6 (Urban Core). The code regulates building form, frontage types, street relationships, and massing rather than just permitted uses. Residential uses in T3 (Sub-Urban) are primarily single-family; T4 through T6 allow increasingly dense multifamily.
Are Airbnb and vacation rentals allowed in Miami?
Yes, with licenses. A Florida DBPR (Department of Business and Professional Regulation) Vacation Rental License is required statewide. Miami has additional local requirements. Miami-Dade County also regulates vacation rentals. Miami has some grandfathered STR restrictions from pre-2011 ordinances. All rentals must pay 13% Miami-Dade Tourist Development Tax. Platforms like Airbnb and VRBO collect and remit applicable taxes.
What are the hurricane wind requirements for building in Miami?
Miami-Dade County is in a High-Velocity Hurricane Zone (HVHZ) — the most stringent wind resistance requirements in the US. All construction must comply with Florida Building Code HVHZ provisions. Roofing products require Miami-Dade Notice of Acceptance (NOA) testing approval. Impact-resistant windows and doors required in new construction and substantial improvements. These requirements increase construction costs but provide significant protection.
Is my Miami property in a flood zone?
Miami-Dade County has extensive FEMA-mapped Special Flood Hazard Areas (SFHAs) due to low elevation and coastal location. Many properties are in AE or VE flood zones requiring flood insurance for federally-backed mortgages. Check the FEMA Flood Map Service Center (msc.fema.gov) for your specific parcel. New construction must meet Base Flood Elevation plus freeboard requirements. Miami is actively addressing sea-level rise through infrastructure investments.
How do I find my property's Transect Zone in Miami?
Use the Miami 21 Interactive Map at gis.miamigov.com/Miami21/. Enter your address to find your Transect Zone designation (T3, T4, T5, T6, or District zones). The map shows allowed uses, building form standards, setbacks, and height limits for your property. Miami 21 is the primary zoning document — you can access the full code at the city's planning department website.
Do I need a permit to operate a home business in Miami?
Yes. A Certificate of Use (Home Occupation) is required for operating a business from a residence in Miami. The fee is approximately $75–$200. Restrictions include no on-site clients or customers, no employees who are not residents, no external signage, and business use limited to 20% of floor area. Cottage food businesses under Florida's Cottage Food Law are exempt from local business permits but sales are capped at $250,000 annually.
Source: City of Miami Building Department — Building Regulations. Last verified April 5, 2026. View source