Miami — city ADU rules and incentives

ADU legality: allowed-with-restrictions

Statewith-restrictions (Florida accessory-dwelling framework)

Countyallowed (Miami-Dade County unincorporated zoning)

Cityallowed (City of Miami Municipal / Zoning Code — Accessory Dwelling Units)

Florida partially preempts local ADU restrictions; cities retain authority over design and setbacks. Miami permits ADUs subject to local conditions per its zoning ordinance.

City cost envelope

$269,775 all-in for a 575 sqft ADU (permit + build). Midpoint scenario.

Permit fee bundle: $2,400.

City viability (selected uses)

Long-term rentalyes

Short-term rentalwith-restrictions

Home officeyes

Relative supportyes

Pre-approved ADU plans

Pre-approved plan program.

City of Miami maintains a pre-approved ADU plan catalog to streamline permitting. Pre-approved plans bypass design review and accelerate ministerial approval.

Miami-Dade County — county ADU rules and overlays

County ADU ordinance

Miami-Dade County operates Florida's most mature and heavily-publicized ADU program, documented at the county's dedicated ADU portal (miamidade.gov/global/economy/building/accessory-dwelling-unit-adu.page). Miami-Dade is Florida's most-populous county and operates a two-tier zoning structure: unincorporated Miami-Dade (the Unincorporated Municipal Service Area, UMSA) is governed by the Miami-Dade County Code of Ordinances, Chapter 33 (Zoning), while incorporated municipalities (34 cities including City of Miami, Miami Beach, Coral Gables, Homestead, Hialeah, Kendall is unincorporated, Aventura, Doral, North Miami, Miami Gardens, Miramar is in Broward, Pinecrest, Palmetto Bay, Cutler Bay, etc.) each maintain their own zoning codes. Miami-Dade's county-level ADU ordinance is explicitly designed to address the region's acute housing affordability crisis and is cited by Florida housing-policy researchers as the de facto state benchmark. § 163.31771 FS remains the enabling framework but Miami-Dade's ADU adoption is among the most permissive locally-adopted schemes in Florida.

State-floor overlay: No Florida statewide ADU preemption floor exists as of April 2026. SB 48 / HB 313 (2026 session) is the active preemption bill — Miami-Dade's existing framework would in most respects already exceed the proposed state floor, so enactment would have minor net impact on Miami-Dade UMSA parcels but would materially affect the more-restrictive incorporated cities.

County regulatory overlays

Miami-Dade County administers flood, coastal, HVHZ, Urban Development Boundary (UDB), Everglades-protection, and airport/port overlays. Coastal parcels face extensive AE/VE flood mapping and CCCL exposure; the UDB restricts development west of a designated boundary to protect Everglades water supply; Everglades-restoration overlays affect southwest Miami-Dade; Miami International Airport and PortMiami produce approach and noise overlays.

FEMA Special Flood Hazard Areas (SFHA) — AE and VE zones are extensive along Biscayne Bay, the Atlantic, and inland along drainage canals. Miami-Dade's flat, low-elevation terrain produces AE zones well inland. ADUs in SFHA require elevation, flood vents, and flood-resistant materials; VE zones require pile-foundation or breakaway-wall construction.
High Velocity Hurricane Zone (HVHZ) — Miami-Dade and Broward are the two HVHZ counties. Construction must meet HVHZ wind-load, impact-glazing, roof-covering, and anchor standards. This is the single largest cost differentiator for ADU construction in Miami-Dade relative to most of Florida.
Urban Development Boundary (UDB) / Urban Expansion Area (UEA) — The UDB separates urbanized Miami-Dade from the Everglades Agricultural Area and the Water Conservation Areas to the west. Development — including ADUs — is generally prohibited west of the UDB without a CDMP amendment. This constrains ADU development on west-county parcels.
Coastal Construction Control Line (CCCL) — Atlantic-front parcels seaward of the CCCL require state DEP permit. Miami-Dade's unincorporated Atlantic frontage is minimal (most coastline is incorporated); affects few UMSA parcels but many Miami Beach, Sunny Isles Beach, Surfside, Key Biscayne parcels.
Everglades Comprehensive Everglades Restoration Plan (CERP) Overlays — Southwest Miami-Dade parcels adjacent to Everglades National Park and within CERP project footprints face enhanced development review.
Miami International Airport (MIA) & Kendall-Tamiami Executive (TMB) Approach Zones — Parcels under MIA and TMB approach/transitional surfaces face height restrictions and, in some cases, noise-attenuation construction requirements.
PortMiami & Biscayne Bay Aquatic Preserve Overlays — Parcels on Biscayne Bay face enhanced setback, water-quality, and mangrove-protection review. An ADU on a bay-adjacent parcel adds environmental-review complexity.
Wildland-Urban Interface (WUI) — Urbanized Miami-Dade has limited WUI exposure. Southwest UMSA parcels abutting the Everglades face moderate exposure.

County permitting (unincorporated parcels)

Permits for ADUs on unincorporated Miami-Dade (UMSA) parcels are issued by the Miami-Dade County Department of Regulatory and Economic Resources (RER), which combines Building and Zoning functions. Miami-Dade UMSA is large and includes major population centers such as Kendall, West Kendall, The Hammocks, Country Walk, Westchester, Richmond Heights, Pinewood, West Little River, and Goulds. Incorporated cities (34 of them) each handle their own permits. The county's ADU portal provides a dedicated application track that is materially faster than a generic addition permit.

DepartmentMiami-Dade County Department of Regulatory and Economic Resources (RER) — Building and Permitting

Address11805 SW 26th Street, Miami, FL 33175

Phone786-315-2000

Florida state — ADU law and programs

State ADU law

Florida does NOT currently have a statewide ADU preemption law in effect. Florida Statutes § 163.31771 (enacted 2004, last amended 2020) is permissive — it authorizes local governments to adopt ADU ordinances but does not require them to. ADU rules are therefore set municipality-by-municipality: Miami-Dade, Orlando, St. Petersburg, Tampa, and a growing set of Florida cities have their own ordinances; many smaller counties and cities still prohibit or restrict ADUs by default. A preemption bill (SB 48 / HB 313) is pending in the 2026 legislative session and is likely to pass given that its 2025 predecessor cleared the Senate 37-0 and House 97-10 before dying on a procedural amendment dispute.

Florida Statutes § 163.31771 — Accessory dwelling units — Permissive (not mandatory) statute. Defines an ADU as 'an ancillary or secondary living unit, that has a separate kitchen, bathroom, and sleeping area, existing either within the same structure, or on the same lot, as the primary dwelling unit.' Authorizes — but does not require — local governments to adopt ordinances allowing ADUs in single-family residential zones. Contains no size caps, no owner-occupancy rules, no HOA preemption. All substantive rulemaking is local.

State financing programs

Florida Housing Finance Corporation (FHFC) does not operate an ADU-specific state loan or grant program. FHFC's primary affordable-housing lever at the ADU tier is the State Housing Initiatives Partnership (SHIP), which distributes state documentary-stamp-tax revenue to all 67 counties and 52 entitlement cities for locally-administered housing programs — some of which may fund ADU construction at the local level (notably Orange County's Affordable ADU Loan Program, run through the Orange County Housing Finance Trust). FHFC's FL Assist down-payment programs and HFA Preferred / HFA Advantage conventional loans apply to ADU-eligible primary residences but do not single out ADUs. Proposed CS/SB 1440 would create a state property-tax exemption of up to 100% of assessed value for an ADU rented at affordable rates.

State housing programs

Florida does not currently operate a statewide pre-approved ADU plan catalog (unlike California or Washington). State-level ADU implementation is driven by (a) the permissive § 163.31771 which lets willing jurisdictions adopt ordinances, (b) SHIP pass-through funding to local ADU programs (Orange County's Affordable ADU Loan Program is the model), and (c) the affordable-housing property-tax exemption under the Live Local Act (SB 102 / SB 328). The Department of Economic Opportunity (DEO) — now reorganized as the Department of Commerce — provides technical assistance to local governments but no statewide ADU-specific mandate or program. Major counties (Miami-Dade, Orange, Pasco, Hillsborough, Pinellas, Broward) have published their own ADU ordinances and guidance documents.

Federal (United States) — ADU-relevant rules and programs

Federal ADU law

The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.

Federal financing programs

Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.

Federal tax credits

There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.

Federal housing programs

HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.

Buena Vista