A growing number of states now require cities to allow accessory dwelling units. Here's which states have statewide ADU laws — and which leave it to local zoning.
ADUs are legal in all 50 states — the real question is whether your state forces local governments to allow them. As of 2026, at least 11 states have passed statewide laws requiring cities to permit ADUs by-right or ministerially (led by California, Oregon, Washington, and most of New England). In the remaining states, local zoning decides — so whether you can build depends on your specific city or county. The table below shows where each state stands; click a state for city-by-city rules.
| State | Statewide ADU Law? | Key Statute | What It Does |
|---|---|---|---|
| California | Yes — statewide mandate | Gov. Code §§66310-66342 | Up to 1,200 sq ft detached; 4 ft setbacks; no parking near transit; no owner-occupancy; 60-day ministerial approval |
| Oregon | Yes — statewide mandate | HB 2001 / ORS 197.312 | ADUs required in single-family zones of larger cities; no off-street parking mandate |
| Washington | Yes — statewide mandate | HB 1337 (2023) | Cities must allow up to 2 ADUs per lot; no owner-occupancy mandate; parking can't be required within ½ mile of major transit (otherwise limited to 1-2 spaces by lot size) |
| Maine | Yes — statewide mandate | LD 2003 (2022) | At least 1 ADU allowed by-right on single-family lots statewide |
| Vermont | Yes — statewide mandate | Act 47 / 24 V.S.A. §4412 | 1 ADU allowed by-right with single-family home statewide |
| New Hampshire | Yes — statewide mandate | RSA 674:71-73 | 1 attached ADU allowed by-right in any single-family zone |
| Massachusetts | Yes — statewide mandate | Affordable Homes Act §8 (2024) | ADUs by-right in single-family zones in all 351 municipalities (effective 2025) |
| Connecticut | Partial — opt-out | PA 21-29 | ADUs allowed by-right statewide unless a town formally opts out |
| Rhode Island | Yes — statewide mandate | RIGL §45-24-37 (2024) | 1 ADU allowed by-right on owner-occupied single-family lots |
| Montana | Yes — statewide mandate | SB 528 (2023) | ADUs required by-right in larger cities' single-family zones |
| Utah | Partial — internal ADUs | HB 82 (2021) | Internal ADUs allowed in most single-family zones; detached up to local rules |
| Arizona | Yes (large cities) | HB 2720 (2024) | Cities over 75,000 must allow ADUs by-right in single-family zones |
| Colorado | Yes (large cities) | HB 24-1152 | Larger cities must allow at least 1 ADU in single-family zones |
| Nevada | Reform underway | AB 396 (2025) | Large cities/counties must adopt ADU ordinances by July 1, 2026 |
| Hawaii | Partial — county-led | Act 39 / county codes | ADUs ('ohana units') allowed via county ordinances; Honolulu by-right on many lots |
| Texas | No statewide law — local control | Local zoning | Each city decides; Austin permissive, Fort Worth allows accessory-only ADUs under §5.301 |
| Florida | No statewide mandate — local control | Live Local Act; SB 48 failed 2026 | Local rules govern; SB 48 statewide mandate died in the House in 2026 |
| New York | Local control (NYC pilot) | Local zoning; NYC City of Yes | No statewide mandate; NYC expanded ADU eligibility via City of Yes (2024) |
| Illinois | Local control | Local zoning | Decided by city; Chicago expanded its ADU program citywide |
| Georgia | Local control | Local zoning | Decided by city; Atlanta and Savannah allow ADUs in many residential zones |
| North Carolina | Local control | Local zoning | Decided by city; Durham, Raleigh, and Charlotte permit ADUs locally |
| Minnesota | Local control | Local zoning | Decided by city; Minneapolis and St. Paul allow ADUs citywide |
| Pennsylvania | Local control | Local zoning | Decided by city; Pittsburgh permits ADUs in residential districts |
"Statewide mandate" means the state requires local governments to allow ADUs; "local control" means each city or county sets its own rules. Laws change frequently — verify with your local planning department.
We track detailed ADU rules for 23 states. Click a state for city comparisons.
3 cities covered. Average ADU-friendliness score: 3.7/10.
View Alabama ADU laws →7 cities covered. Average ADU-friendliness score: 6.0/10.
View Arizona ADU laws →36 cities covered. Average ADU-friendliness score: 7.2/10.
View California ADU laws →3 cities covered. Average ADU-friendliness score: 7.7/10.
View Colorado ADU laws →1 cities covered. Average ADU-friendliness score: 7.0/10.
View District of Columbia ADU laws →4 cities covered. Average ADU-friendliness score: 4.8/10.
View Florida ADU laws →2 cities covered. Average ADU-friendliness score: 5.5/10.
View Georgia ADU laws →1 cities covered. Average ADU-friendliness score: 7.0/10.
View Hawaii ADU laws →2 cities covered. Average ADU-friendliness score: 7.0/10.
View Illinois ADU laws →6 cities covered. Average ADU-friendliness score: 6.3/10.
View Massachusetts ADU laws →3 cities covered. Average ADU-friendliness score: 5.3/10.
View Michigan ADU laws →2 cities covered. Average ADU-friendliness score: 8.5/10.
View Minnesota ADU laws →2 cities covered. Average ADU-friendliness score: 4.0/10.
View Nevada ADU laws →3 cities covered. Average ADU-friendliness score: 7.0/10.
View New Jersey ADU laws →3 cities covered. Average ADU-friendliness score: 4.7/10.
View New York ADU laws →3 cities covered. Average ADU-friendliness score: 7.0/10.
View North Carolina ADU laws →5 cities covered. Average ADU-friendliness score: 7.6/10.
View Oregon ADU laws →1 cities covered. Average ADU-friendliness score: 5.0/10.
View Pennsylvania ADU laws →1 cities covered. Average ADU-friendliness score: 7.0/10.
View Tennessee ADU laws →5 cities covered. Average ADU-friendliness score: 6.0/10.
View Texas ADU laws →1 cities covered. Average ADU-friendliness score: 8.0/10.
View Utah ADU laws →2 cities covered. Average ADU-friendliness score: 6.0/10.
View Virginia ADU laws →5 cities covered. Average ADU-friendliness score: 7.6/10.
View Washington ADU laws →We're expanding coverage to all 50 states. Request a state to help us prioritize.
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