How to get ADU Permit in Miami-Dade County
Insights
November 3, 2025
minute read
Key Takeaways
Miami-Dade County permits ADUs on properties meeting minimum 7,500 square foot lot sizes, with over 50,000 residential lots potentially eligible based on size and zoning
A pre-approved ADU Blueprint program can reduce permit wait times by up to 40%, streamlining the approval process significantly
RU-1 zoned ADUs are limited to a maximum of 800 square feet, with strict setback requirements and hurricane-resistant construction standards
Total permit fees typically range from $1,000–$3,000 depending on project scope, not including utility connection costs
All ADUs must meet High-Velocity Hurricane Zone (HVHZ) standards with hurricane-resistant windows, doors, and construction capable of withstanding extreme wind loads
Mesocore's modular ADU solution includes factory-installed, Intertek-certified MEP systems and 180 mph wind resistance, eliminating rough-in inspections in some jurisdictions and accelerating the entire permitting timeline
Property owners must apply for and renew a Certificate of Use, which remains non-transferable upon property sale
Miami-Dade County has positioned itself as one of Florida's most progressive jurisdictions for ADU development, implementing streamlined permitting processes to address the region's significant housing shortage. With hurricane-resistant construction mandatory and HVHZ standards applying throughout the county, selecting the right ADU solution from the start is critical. For homeowners in eligible zones, Mesocore's modular ADU offers a turnkey solution engineered to meet or exceed Miami-Dade's stringent HVHZ wind codes with 180 mph wind rating and factory-tested structural integrity.
Understanding ADUs in Miami-Dade County
An Accessory Dwelling Unit (ADU) in Miami-Dade County is a residential unit—either attached or detached—located on the same lot as a principal single-family dwelling. It includes its own kitchen, bathroom, and sleeping area, designed for independent occupancy separate from the main house.
ADUs serve multiple purposes that make them attractive to property owners:
Rental income generation: About 60% serve multigenerational families, while others generate rental income from unrelated tenants
Family housing solutions: Guest suites, in-law units, caregiver quarters, or private offices
Property value enhancement: Properties with permitted ADUs see resale value increases in some cases
Affordable housing contribution: Miami-Dade's ordinance could add housing stock over several years
Common ADU Types Permitted in Miami-Dade
Miami-Dade permits several ADU configurations depending on lot characteristics and zoning:
Detached ADUs: Separate structures in the backyard, most common type
Attached ADUs: Connected to main house with separate entrance
Garage conversions: Converting existing garage space to living quarters
Backyard cottages: Small standalone structures designed as complete dwelling units
All types must comply with building codes, zoning regulations, and strict setback, parking, and hurricane-resistant construction standards to ensure community compatibility.
Miami-Dade County ADU Requirements: Zoning, Setbacks, and Lot Size
Understanding Miami-Dade's dimensional and zoning requirements is essential before beginning the ADU permitting process.
Lot Size and Dimensional Standards
Properties must meet specific minimum lot size requirements for ADU eligibility. Most residential lots require at least 7,500 square feet to qualify for ADU construction. This threshold ensures adequate space for both the primary residence and ADU while maintaining proper setbacks and yard requirements.
ADU size restrictions vary by zoning district:
RU-1 zones: ADUs limited to a maximum of 800 square feet
Other residential zones: Size limits vary but typically range from 400–1,000 square feet
Floor Area Ratio (FAR): Total building coverage including ADU cannot exceed zoning district FAR limits
Setback Rules and Parking Requirements
Setback requirements determine how close an ADU can be built to property lines. Setback requirements vary by zoning district and are defined in Miami-Dade Code Chapter 33. ADU-specific setback standards apply and should be verified for your specific property's zoning classification.
Parking requirements add another layer of compliance. Most ADU applications require at least one additional off-street parking space beyond what's required for the primary residence, though specific requirements depend on the zoning district and ADU size.
The Pre-Approved ADU Blueprint Program
Miami-Dade County introduced a pre-approved ADU Blueprint program to streamline permitting and reduce barriers to legal ADU construction. This program allows property owners to select from certified designs that have already undergone architectural and engineering review.
Benefits of Using County-Approved Blueprints
The blueprint program offers significant advantages:
Faster approvals: Permit approval rates are high when using county-approved blueprints
Reduced revision cycles: Pre-vetted designs minimize back-and-forth during plan review
Clear expectations: Homeowners know requirements upfront, avoiding common pitfalls
Cost certainty: Fewer revision cycles mean lower professional service fees
However, only property owners may apply for and renew a Certificate of Use for ADUs, and transfers of ownership require new approvals—an important consideration for future property sales.
Step-by-Step ADU Permit Application Process
The ADU permitting process in Miami-Dade involves multiple phases requiring careful coordination and complete documentation.
Phase 1: Feasibility and Site Review
Before investing in plans and applications, verify your property's eligibility:
Confirm zoning eligibility: Check if your property is in an ADU-permitted zone
Verify lot size: Ensure property meets minimum square footage requirements
Review setback requirements: Confirm adequate space exists for proper setbacks
Check utility capacity: Verify existing utilities can support additional dwelling
Assess site conditions: Consider drainage, tree protection, and access
Mesocore offers a professional site plan service for $200 (fully refundable if you decide not to proceed) that creates a site plan confirming feasibility and determining whether your project meets Miami-Dade's zoning and setback requirements.
Phase 2: Prepare Required Documentation
Comprehensive documentation accelerates the approval process:
Property survey: Current survey showing lot dimensions and existing structures
Site plan: Detailed plan showing proposed ADU location, setbacks, and parking
Architectural drawings: Floor plans, elevations, foundation plans, and roof framing
Engineering calculations: Structural calculations sealed by licensed Florida engineer
MEP drawings: Mechanical, electrical, and plumbing plans with proper seals
Proof of ownership: Deed or title documentation
Contractor information: Licensed contractor details and insurance verification
All architectural plans require digitally sealed signatures from licensed professionals. Applications lacking these verifiable seals will be rejected outright.
Phase 3: Submit Building Permit Application
Once documentation is complete, submit your application through Miami-Dade's online permitting portal. The typical review timeline for a straightforward ADU project is 6–12 months from permitting to move-in.
Phase 4: Plan Review and Approval
Miami-Dade's building department reviews applications for compliance with:
Florida Building Code requirements
HVHZ wind resistance standards
Zoning and setback compliance
Structural engineering adequacy
Fire safety and egress requirements
Energy code compliance
The county's commitment to safety means construction passes inspections at high rates when proper planning and professional contractors are used.
Phase 5: Construction and Inspections
Once the permit is issued, construction can begin. Traditional site-built ADUs require multiple inspections:
Foundation inspection
Framing inspection
Rough plumbing, electrical, and mechanical inspections
Insulation inspection
Final inspections for all systems
However, Mesocore ADUs streamline this process significantly. All Mechanical, Electrical, and Plumbing (MEP) systems are factory-installed and Intertek-certified before delivery. This eliminates rough-in inspections on-site for plumbing, mechanical, and electrical systems in some jurisdictions, reducing total inspection requirements and accelerating construction timelines.
Miami-Dade HVHZ Building Code Compliance
Miami-Dade County and Broward County are Florida's only designated High-Velocity Hurricane Zones (HVHZ), subjecting all new construction to the most stringent wind resistance requirements in the United States.
What HVHZ Certification Means for Your ADU
HVHZ certification requires construction to withstand extreme hurricane conditions with design wind speeds reaching 180 mph in coastal areas. This mandatory standard protects residents and property investments while ensuring ADUs can survive major hurricane events without catastrophic failure.
Key HVHZ requirements include:
Hurricane impact windows and doors: All glazed openings must resist wind-borne debris impacts
Enhanced roof attachment: Roof systems must be secured with redundant connections to prevent uplift
Structural tie-downs: Continuous load path from roof to foundation
Wind-resistant materials: All exterior materials must meet Product Approval standards
NOA certificates: Notice of Acceptance required for all hurricane-resistant products
Wind Rating and Impact-Resistant Materials
All ADU components exposed to wind and debris must carry Florida Product Approval and meet specific impact resistance standards. Windows and doors must withstand impacts from a 9-pound 2x4 board traveling at 34 mph, then maintain integrity under positive and negative design pressures.
Mesocore's HVHZ Advantage: Every Mesocore ADU is engineered to meet or exceed Miami-Dade's HVHZ wind codes with 180 mph wind rating. The robotically welded steel core structure, hurricane impact windows, and impact-rated doors are included as standard features. This built-in compliance can accelerate permit approval since structural engineering is already documented and tested at the factory level.
ADU Permit Fees and Costs in Miami-Dade County
Understanding the complete cost structure helps homeowners budget appropriately for ADU development.
Breakdown of Miami-Dade ADU Permit Fees
Permit fees vary based on ADU size and construction value, with typical baseline costs ranging from $1,000–$3,000 for the building permit itself. This includes:
Plan review fees: Typically 40% of total permit cost
Building permit fees: Based on construction valuation
Inspection fees: Included in building permit cost
Certificate of Use application: Required for legal occupancy
Impact Fees and Utility Connection Charges
Beyond permit fees, additional costs include:
Utility connection fees: Wastewater capacity, water service, and electrical connections
Impact fees: May apply depending on lot location and existing infrastructure
School impact fees: May apply in certain districts
Tree removal permits: If protected trees require removal
Total "all-in" costs for completing an ADU project typically range from $100,000–$200,000+ depending on size, finishes, and site conditions.
Working with Miami-Dade Building Department and Regulatory Agencies
Effective navigation of Miami-Dade's regulatory environment requires understanding key contacts and resources.
Miami-Dade Building Department Resources
The Building Department coordinates all permitting activities and code enforcement:
Main phone: Contact the Building Department for permit inquiries and application status
Online portal: Submit applications and track permit status digitally
Pre-application consultation: Schedule meetings to verify requirements before applying
Certificate of Use Requirements
All ADUs require a Certificate of Use (CU) for legal occupancy. Only the property owner may apply for and renew a Certificate of Use for ADUs. Transfers of ownership require new approvals.
This means when you sell your property, the new owner must apply for a new Certificate of Use—the existing CU does not automatically transfer.
Utility Connections and Infrastructure Requirements
Connecting your ADU to water, sewer, and electrical utilities requires coordination with multiple service providers.
Water and Sewer Connection Process
ADUs must connect to Miami-Dade's municipal water and sewer systems:
Water service: Application through Miami-Dade Water and Sewer Department
Sewer connection: Capacity verification and connection permit required
Separate meters: ADUs can have separate water meters for independent tenant billing
Backflow prevention: Required devices to protect potable water supply
Electrical Service and Metering Options
Standard electrical connection involves either sharing the main house electrical service or installing a separate meter for independent billing.
However, Mesocore ADUs offer a third option that may reduce costs considerably. Each Mesocore unit includes a 6 kW solar array with two 10 kWh lithium-ion batteries for energy storage. Some jurisdictions, including Palm Beach County, have approved Mesocore ADUs to operate independently from the main house—no utility hookup or separate meter required. This off-grid capability might cut connection fees, meter costs, and ongoing utility expenses while maintaining full functionality, though verification with Miami-Dade utilities is recommended for your specific property.
Septic System Capacity Considerations
Properties using septic systems must verify adequate capacity for the additional dwelling unit. Most ADU applications require septic system evaluation and potential expansion to handle increased wastewater flow. Many homeowners can connect to existing septic systems if they're large enough to handle additional plumbing, though this determination occurs during the feasibility phase.
Site Preparation and Foundation Requirements
Proper site preparation and foundation construction form the literal foundation for ADU success.
Foundation Options for Miami-Dade ADUs
Miami-Dade's HVHZ requirements and high water table influence foundation choices:
Slab-on-grade: Most common for detached ADUs
Concrete pier foundation: Suitable for elevated structures or flood-prone areas
Elevated foundation: Required in flood zones to meet FEMA requirements
Mesocore's Model E uses a durable concrete pier foundation with 8 piers, designed specifically for Miami-Dade conditions. Local licensed contractors install the foundation during the site preparation phase, with Mesocore providing detailed engineering specifications.
Soil Testing and Flood Zone Compliance
Before foundation construction:
Soil testing: Geotechnical analysis determines bearing capacity and soil composition
Elevation certificate: Required for properties in flood zones
Flood zone verification: Determines if elevated foundation is mandatory
Drainage plan: Ensures proper stormwater management
Properties in Special Flood Hazard Areas must meet additional elevation and flood-resistant construction requirements beyond standard building code.
ADUs in the National Context: Miami-Dade's Progressive Approach
Miami-Dade's ADU regulations place the county among the more progressive jurisdictions nationally for accessory dwelling unit development.
States with ADU-Friendly Laws
Several states have enacted legislation encouraging ADU development:
California: Statewide ADU mandates require cities to allow ADUs with minimal restrictions
Oregon: State law requires ADU allowances in most single-family zones
Washington: Growing ADU permissions in urban areas
Florida: Local control with increasing county-level adoption
Texas: Varies by municipality with expanding allowances
Georgia: Limited but growing ADU acceptance
Miami-Dade urban planning recommends ADUs as a top solution to affordable housing, positioning the county as a leader within Florida's regulatory landscape.
How Miami-Dade Compares to Other Florida Counties
Within Florida, Miami-Dade's approach is more structured than many counties:
Pre-approved blueprint program: More advanced than most Florida jurisdictions
Clear zoning guidelines: Well-defined eligibility areas and requirements
Streamlined permitting: 40% faster with approved blueprints
HVHZ standards: Most stringent construction requirements protecting residents
For property owners exploring ADU options across multiple markets, Mesocore serves Florida, Texas, Georgia, and Southeast markets with IBC-approved modular ADUs registered in the Florida DBPR program, with expansion to California and Hawaii coming soon.
Common ADU Permit Challenges and How to Overcome Them
Understanding frequent obstacles helps applicants avoid costly delays and denials.
Dealing with HOA Restrictions
Homeowners associations may prohibit or restrict ADU construction regardless of county allowances. Before beginning the permitting process:
Contact your HOA to confirm ADUs are allowed by bylaws
Request architectural review guidelines if applicable
Submit HOA application alongside county permit application
Address deed restrictions that may prohibit additional structures
Addressing Setback and Design Issues
Common issues include:
Insufficient setbacks: Redesign ADU location or request variance
Lot coverage exceeded: Reduce ADU size to meet coverage limits
Height restrictions: Lower roof line or choose different design
Tree protection conflicts: Relocate ADU to avoid protected tree critical root zones
Using county-approved blueprints significantly reduces these conflicts by ensuring designs comply with typical lot configurations.
What to Do If Your Permit Is Denied
If your initial application is denied:
Review denial reasons: Understand specific code violations or deficiencies
Consult with building department: Discuss potential solutions
Revise plans: Address identified issues with licensed professionals
Resubmit application: Most denials can be resolved through revision
Request variance: If code compliance is impossible, formal variance process may provide relief
Why Mesocore is the Smart Choice for Miami-Dade ADUs
For Miami-Dade homeowners navigating the complex ADU permitting landscape, Mesocore offers a turnkey solution specifically engineered for South Florida's demanding conditions.
Factory-Certified Systems Streamline Approvals
Mesocore's modular construction approach addresses Miami-Dade's most challenging permit requirements. All Mechanical, Electrical, and Plumbing systems are factory-installed and Intertek-certified before delivery. This third-party certification eliminates rough-in inspections on-site for these systems in some jurisdictions, reducing total inspection requirements and accelerating construction timelines that typically stretch 6-12 months.
The robotically welded steel core arrives as a 20-foot container with all electrical, solar, and plumbing systems factory-tested. On-site installation can be completed in as little as 10 days (410 sq. ft. ADU), compared to 4-6 months for traditional site-built construction.
Exceeds HVHZ Requirements with 180 MPH Wind Rating
Miami-Dade's High-Velocity Hurricane Zone standards represent the most stringent construction requirements in the United States. Mesocore's Model E is engineered to withstand 180 mph wind resistance, exceeding local requirements. The structure includes:
Hurricane impact windows and doors as standard equipment
Robotically welded steel core for exceptional structural strength
Pre-engineered designs meeting Florida Building Code and IBC approval
Registered in Florida DBPR modular home program
This built-in compliance accelerates permit approval by providing complete structural engineering documentation and factory test results.
Integrated Solar Reduces Utility Costs and Connection Fees
Each Mesocore unit includes a 6 kW solar system with 14 roof-mounted PV panels and two 10 kWh lithium-ion batteries for energy storage. This integrated system provides several advantages:
Save on utility bills: Solar and battery storage can reduce or eliminate electric costs
Potential off-grid operation: In jurisdictions like Palm Beach County, Mesocore ADUs have been approved to operate independently without utility hookup or separate meter
Reduced connection fees: Off-grid capability might eliminate meter installation costs and ongoing utility expenses
Higher rental income: Zero-energy design makes ADUs more attractive to tenants
The factory-installed exterior mechanical room with all plumbing, electric, and solar equipment pre-tested simplifies connection to Miami-Dade's municipal systems and makes separate meter installation straightforward if required.
Financing Options Make ADU Investment Accessible
Mesocore partners with multiple lenders to provide flexible financing:
Ocean Capital Lending offers programs designed specifically for ADU projects, with financing that covers land, construction cost, and converts to a mortgage.
HFS Financial provides personal loans of $1,000–$300,000 with no home equity or appraisal required, offering 100% upfront contractor funding, fixed rates from 7.99%, and terms up to 20 years for loans over $15,000. This specialized home improvement and ADU financing features instant pre-qualification and no dealer fees for Miami-area contractors.
With Mesocore's Model E starting at $129,000 factory MSRP, these financing options help manage upfront costs while rental income generates positive cash flow.
Complete Support from Site Plan to Move-In
Mesocore provides comprehensive support throughout the permitting and construction process:
Site plan creation: $200 refundable deposit for professional site plan confirming feasibility
Stamped drawings: Complete engineered construction drawings and structural calculations
Permitting assistance: Guidance through Miami-Dade's application process
Factory installation: Professional installation team completes on-site assembly
Warranty and support: Ongoing support for your ADU investment
The 410 square foot layout includes 1 bedroom, 1 full bathroom, complete kitchen with stainless steel appliances, and luxury vinyl plank flooring—perfect for a guest suite, in-law unit, home office, or rental property generating monthly income.
For Miami-Dade homeowners seeking a proven, hurricane-resistant ADU solution that streamlines the permitting process and accelerates time to occupancy, schedule a consultation or tour the showroom.
Conclusion
Miami-Dade County's ADU program offers property owners a valuable opportunity to add housing, generate rental income, and increase property value while helping address the region's housing shortage. Understanding the permitting requirements—from minimum lot sizes and setback rules to HVHZ compliance and utility connections—is essential for a successful project. The county's pre-approved blueprint program and streamlined processes make ADU development more accessible than in many jurisdictions, though careful planning and professional guidance remain critical.
For homeowners ready to move forward, Mesocore's modular ADU solution is purpose-built for Miami-Dade's demanding conditions, combining factory-certified systems, 180 mph wind resistance, and integrated solar to accelerate permitting and reduce long-term costs. With comprehensive support from site planning through move-in, Mesocore helps you navigate the process efficiently and deliver a hurricane-resistant, energy-efficient ADU that meets all county requirements.
Frequently Asked Questions
Who can build an ADU in Miami-Dade County?
Eligibility depends on zoning and lot size. Most single-family lots must be at least 7,500 square feet and meet setback, parking, and other zoning requirements before an ADU is allowed.
How large can my ADU be and what zoning rules apply?
In RU-1 zones, ADUs are capped at 800 square feet, while other residential zones may allow different sizes within their limits. You must still meet district-specific setbacks, lot coverage, and parking requirements.
Will the Pre-Approved ADU Blueprint program speed things up?
Yes. Choosing a county pre-approved blueprint can reduce permit wait times by up to 40 percent by minimizing revision cycles and clarifying requirements upfront.
What permits and fees should I expect, and do I need a Certificate of Use?
Typical building permit fees run about $1,000–3,000 depending on scope, not including utility connections or any applicable impact fees. A Certificate of Use is required for legal occupancy, must be obtained and renewed by the property owner, and does not transfer automatically when the property is sold.
What hurricane standards and inspections will my ADU face, and can modular help?
All ADUs must meet High-Velocity Hurricane Zone standards, including impact-rated windows/doors and HVHZ-compliant structural design. Modular options with factory-installed, Intertek-certified MEP systems can eliminate on-site rough-in inspections in some jurisdictions, helping shorten overall timelines while still passing required finals.
