What's Required in Miami
- ADUs are allowed on properties in T3, T4, T5, and T6 transect zones under Miami 21
- Maximum ADU size: typically 50% of primary structure or 750 sq ft, whichever is less
- Separate utility connections (water, sewer) required for detached ADUs
- Florida Building Code (HVHZ) requirements apply to all construction
- Impact fees for schools, parks, and utilities are typically required
- Detached ADUs must meet setbacks specified in Miami 21 zoning code
- Owner-occupancy may be required — check current Miami 21 regulations
- Licensed architect required for most ADU permit applications
Miami ADU Permit Fees Breakdown
| Fee Type | Typical Amount |
|---|---|
| Building Permit (valuation-based) | $1,500–$5,000 |
| Electrical Permit | $300–$800 |
| Plumbing Permit | $300–$700 |
| Mechanical/HVAC Permit | $200–$600 |
| Impact Fees (schools, parks, utilities) | $2,000–$8,000+ |
| Planning Review Fee | $500–$1,500 |
How Much Does an ADU Permit Cost in Miami?
Budget $2,000–$10,000+ for the Miami permit itself (valuation-based on construction cost), issued by the City of Miami Building Dept. — but treat that as the entry fee, not the total. ADUs are full dwelling units, so the permit stack usually includes building, electrical, plumbing, and mechanical trade permits, plus plan review. One local note: impact fees, utility connection fees may apply. Get an itemized fee estimate from the department before finalizing your budget; the spread between a simple conversion and a new detached build is wide.
ADU Size Limits and Zoning Rules in Miami
Before drawing plans, check the two gates that sink most ADU projects: size and zoning. Size ceilings vary by lot and ADU type (attached, detached, or conversion), so confirm your specific configuration. Other recorded conditions: owner-occupancy may be required — check current Miami 21 regulations. Setbacks, height limits, and utility connections layer on top of those rules. The City of Miami Building Dept. can confirm what your specific lot allows — worth doing before you pay for architectural drawings rather than after.
How to Get a ADU Permit in Miami
Check Miami 21 Zoning
Miami uses the Miami 21 form-based code. Confirm your transect zone at gis.miami.gov/miamizoning and verify ADU allowances for your zone.
Hire Architect & Contractor
ADU permits require plans by a Florida-licensed architect and construction by a Florida-licensed general contractor.
Pre-Application Meeting
Schedule a pre-application meeting with the City of Miami Planning Department to review your project before submitting.
Submit Full Permit Package
File building, electrical, plumbing, and mechanical permits together through Miami's iBuild portal. Include full construction drawings, survey, and energy calculations.
Plan Review (2–6 months)
Expect a lengthy review process — ADU projects go through planning, building, zoning, and environmental reviews. Expedited review is available for an additional fee.
Construction & Inspections
Multiple inspections required throughout construction. Final inspection and certificate of occupancy required before ADU can be occupied.