Spring ADU Rules by City & State (2026)

Most Restrictive

1. 1
   Miami Beach, FL800-1,200 sq ft (varies by district)

   Miami Beach restricts ADUs under its Land Development Regulations. ADUs are permitted only in certain single-family residential zoning districts, must maintain the external appearance of a single-family home, and are subject to strict size and design requirements consistent with Miami-Dade County ADU standards.

2. 2
   Paterson, NJ

   Paterson's zoning ordinance flatly bars any accessory building, garages, sheds, converted outbuildings, from being used for human habitation in residential zones, closing off garage apartments and backyard ADUs.

3. 3
   Seminole, FLYes, building permit

   Seminole's land development code restricts accessory dwelling units. Most single-family zones allow only one principal dwelling, and second living units require special approval through the Planning and Zoning Division.

4. 4
   Springfield, IL

   Springfield's zoning code expressly prohibits using any detached garage, accessory building, or structure as a dwelling unit, so a freestanding accessory dwelling unit (ADU) is not permitted under Zoning Ordinance Section 155.068(b)(2). Illinois has no statewide ADU law in force (HB 1813 remains pending), so the local ban governs.

5. 5
   Marathon County, WI

   Marathon County zoning flatly bars using a detached garage, shed, or other accessory building as a separate dwelling unit, and residential lots are capped at one house anyway.

6. 6
   Cape Coral, FLMaximum size is 800 sq ft or 30% of the primary structure, whichever is less

   Cape Coral does not currently permit traditional accessory dwelling units (ADUs) with full kitchens. Under Land Development Code Section 5.2.11, only detached 'guest houses' are allowed, and only in the Residential Estate (RE) zoning district on lots with an existing principal residence. Guest houses cannot contain a kitchen or even the electrical/gas connections for a stove or oven, may not exceed 800 sq ft or 30% of the primary structure (whichever is less), are limited to one story (14 ft max), and cannot be rented as separate dwellings. Florida has no statewide ADU mandate.

7. 7
   Cherry Hill, NJ

   Cherry Hill Township's zoning ordinance flatly bans accessory dwelling units. Section 40-401J lists "Accessory dwelling units, 'mother-in-law' suites, and the like" among nine uses "specifically prohibited" townshipwide, alongside junkyards, mobile homes, and drive-in restaurants, so there is no permit path to add a second dwelling unit to a single-family lot.

8. 8
   Butte County, CA1,200 sq ft (minimum 150 sq ft)

   Butte County permits accessory dwelling units (ADUs) and junior ADUs in unincorporated areas served by municipal water and sewer, with ministerial approval, 4-foot side/rear setbacks, and size caps of 500 sq ft (JADU) or 1,200 sq ft (detached ADU); short-term rentals under 30 days are prohibited.

9. 9
   Coral Gables, FLRequired

   Coral Gables strictly regulates accessory dwelling units through its Zoning Code and Board of Architects review. ADUs are limited to ancillary apartments in select residential zoning districts with significant size, design, and owner-occupancy requirements enforced by Development Services.

10. 10
    Des Plaines, ILShed, gazebo, pergola, detached garage

    Des Plaines has no accessory dwelling unit (ADU) or coach-house ordinance; under Zoning Code Section 12-8-1 a permitted residential accessory structure is limited to a shed, gazebo, pergola, or detached garage and cannot be a separate dwelling, and Illinois has no enacted statute requiring cities to allow ADUs.