Updated 2026
ADU Laws by State
ADU regulations vary dramatically by state — and often by city within a state. Select your state for a complete guide covering permit requirements, costs, setbacks, and recent law changes.
State Guides
California
Very PermissiveCalifornia has some of the most permissive ADU laws in the country.
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Oregon
PermissiveOregon requires cities over 2,500 residents to allow ADUs on all single-family lots.
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Washington
PermissiveWashington requires most cities to allow two ADUs per single-family lot under HB 1337 (2023) — no owner-occupancy required, impact fees capped at 50%.
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Texas
ModerateTexas ADU rules are set at the city level — there is no state preemption.
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Arizona
PermissiveArizona now requires ADUs to be allowed by right statewide: HB 2720 (2024) covers cities with 75,000+ residents, and HB 2928 (2025) extended nearly identical rules to counties, effective January 1, 2026.
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Florida
ModerateFlorida ADU rules are set at the city and county level — there is no statewide preemption for single-family zones.
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Nevada
PermissiveNevada's AB 396 (2025) required every county with 100,000+ residents and every city with 60,000+ residents — Clark County, Las Vegas, Henderson, North Las Vegas, Reno, and Sparks — to allow ADUs by right by July 1, 2026.
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Colorado
PermissiveColorado passed statewide ADU legislation in 2024, requiring most municipalities to allow ADUs.
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New York
ModerateNew York passed statewide ADU legislation in 2022 requiring municipalities in the New York City metro area to allow ADUs.
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New Jersey
PermissiveNew Jersey passed landmark ADU legislation in 2024 requiring municipalities to allow ADUs on single-family lots statewide.
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Massachusetts
PermissiveMassachusetts passed the Affordable Homes Act in 2024, which includes a statewide provision allowing ADUs by right on single-family lots.
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Minnesota
PermissiveMinnesota passed statewide ADU legislation in 2023 as part of a broad housing package, requiring cities to allow ADUs on single-family lots.
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Montana
PermissiveMontana passed sweeping zoning reform legislation in 2023, including SB 245, which requires cities to allow ADUs statewide and limits impact fees.
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North Carolina
ModerateNorth Carolina ADU rules are set at the city and county level.
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Georgia
ModerateGeorgia ADU rules are set at the local level.
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Illinois
ModerateIllinois ADU rules are set at the city and county level with no statewide preemption.
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Virginia
PermissiveVirginia's 2023 ADU law (HB 2045/SB 1416) requires all localities to allow ADUs by right in single-family zones — no owner-occupancy needed.
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How State ADU Laws Work
State law sets the minimum standard — cities can be more permissive but not more restrictive than state law allows. California, Oregon, Washington, and Colorado have among the strongest statewide ADU protections.
In states without statewide ADU preemption (like Texas), rules are entirely set at the city level — meaning ADU allowances vary dramatically from one city to the next.