Everything homeowners ask about building an ADU in Miami — answered with 2026 data.
Yes, ADUs are allowed in Limited to select residential zones in Miami, FL. The maximum size for a detached ADU is 400-800 sq ft (varies by district). Attached ADUs can be up to 400-800 sq ft (varies by district). Miami has an ADU-friendliness score of 5/10. Check our full Miami ADU rules page for complete zoning details.
ADU construction in Miami typically costs $180,000-$350,000. The cost per square foot averages $240-$460. Garage conversions are more affordable at $80,000-$180,000, while prefab ADUs cost $120,000-$260,000. Permit fees add $5,000-$8,000 to your budget. See our detailed Miami ADU cost guide.
Detached ADUs in Miami can be up to 400-800 sq ft (varies by district). Attached ADUs are limited to 400-800 sq ft (varies by district). Junior ADUs (JADUs) have a cap of Not allowed. Maximum height is Must not exceed height of principal structure. You are allowed up to 1 ADU per lot on a qualifying lot.
Rear setback: 5 ft (RU-1 district). Side setback: 5 feet. Front setback: 25 feet. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
2 spaces per unit. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required. Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Miami is typically 120-180 days. The plan check process takes approximately 6-8 weeks. Pre-approved plans availability: Not available.
Average ADU rental income in Miami: 1-bedroom units rent for $1,600-$2,200/mo/month, 2-bedroom units for $2,000-$3,000/mo/month. Short-term rentals: Not permitted. Expected ROI: 5-7% annual return.
The minimum lot size for an ADU in Miami is 8,000 sq ft. This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Miami, a garage conversion typically costs $80,000-$180,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.