What States Allow ADUs? The 2026 State-by-State Guide

38 states permit ADUs by right. The other 12 make you work harder for it.

The regulatory environment for accessory dwelling units transformed between 2020 and 2026. California kicked it off. Oregon and Washington followed. By 2026, ADUs are legal by right in 38 states — including some surprises.

The 38 by-right ADU states (2026)

California — SB 9 and SB 1211 make ADUs and JADUs mandatory on most single-family lots. Up to 3 units per parcel in many jurisdictions.

Oregon — HB 2001 (2019) and follow-on legislation. ADUs by right on any residential lot.

Washington — HB 1337 (2023) permits up to 2 ADUs on any lot zoned for single-family.

Colorado — HB24-1152 permits ADUs by right statewide.

Massachusetts — Chapter 358 (2024) requires all municipalities to permit ADUs.

Vermont — S.100 (2023) permits ADUs by right on any residential lot.

Maine — LD 2003 (2022) — one ADU by right on any single-family lot.

Connecticut — Public Act 21-29 requires municipalities to permit ADUs.

Rhode Island — 2023 legislation permits ADUs by right.

New Hampshire — Statewide by-right ADU permission (2017 legislation, updated 2023).

New York — 2024 legislation permits ADUs statewide with local input.

New Jersey — 2024 legislation eases ADU permission across municipalities.

Pennsylvania — Permissive framework with local implementation.

Virginia — 2024 legislation permits ADUs by right statewide.

Maryland — 2024 statewide ADU legislation.

Delaware — Permissive framework.

North Carolina — 2023 legislation eases ADU permits.

South Carolina — Local permission dominant; some statewide easing.

Georgia — Local permission dominant; Atlanta and other metros permissive.

Florida — Local permission dominant; Miami-Dade very permissive.

Alabama — Local permission; Birmingham permissive.

Kentucky — Local permission; Louisville and Lexington permissive.

Tennessee — Local permission; Nashville very permissive.

Ohio — Local permission; Columbus permissive.

Michigan — Local permission; Ann Arbor and Grand Rapids permissive.

Illinois — Local permission; Chicago very permissive.

Indiana — Local permission.

Wisconsin — Local permission; Madison permissive.

Minnesota — Local permission; Minneapolis very permissive (2018 legislation).

Missouri — Local permission; St. Louis permissive.

Kansas — Local permission.

Iowa — Local permission.

Nebraska — Local permission; Omaha permissive.

Arizona — Local permission; Phoenix and Tempe permissive.

New Mexico — Local permission; Santa Fe permissive.

Nevada — Local permission; Las Vegas metro permissive.

Utah — Local permission; Salt Lake City metro permissive.

Texas — Local permission dominant; Austin very permissive.

The 12 restrictive / local-only states (2026)

Wyoming — No statewide permission; local restrictive. Idaho — Local permission dominant; Boise permissive. Montana — Local permission dominant. North Dakota — Local permission dominant. South Dakota — Local permission dominant; restrictive in most jurisdictions. Oklahoma — Local permission; OKC permissive. Arkansas — Local permission dominant. Mississippi — Restrictive statewide. Louisiana — Local permission dominant; New Orleans permissive. West Virginia — Local permission dominant. Alaska — Local permission dominant. Hawaii — Local permission; specific district rules.

Note: this list represents state-level permission. Even in restrictive states, specific cities may permit ADUs. Check your specific city's ordinance regardless of state.

The layout — what "by right" actually means

By-right permission — the state has preempted local bans and requires municipalities to approve ADU applications meeting stated criteria. Typical criteria: minimum lot size, maximum ADU size, setback compliance, parking requirements.

Non-by-right / local permission — each city/county sets its own rules. Some cities permit; others prohibit.

What by-right doesn't override:

• Coastal Commission zones (California)
• Historic districts
• HOA covenants (private restrictions)
• Environmental hazard zones
• Some transportation-corridor overlays

Two builders across permission spectrum

Villa — California-based, ships to CA, WA, CO, OR. Purpose-built for permissive by-right states.

Abodu — California + Pacific Northwest. Similarly positioned for by-right markets.

Financing math across permission environments

Same $250K ADU build:

By-right state (e.g., California):

• Permit process: 4-8 weeks typical
• HomeStyle Renovation at 7% = $1,660/month
• Rental yield: $1,600-$2,200/month
• Cash flow positive from month 1

Non-by-right state (e.g., Mississippi):

• Permit process: 6-18 months if approved at all
• Same financing but higher risk of denial
• Rental yield depends on legalization

Choose to build ADU by right if...

• Your state permits ADUs by right
• Your parcel meets state-defined criteria
• Your rental market supports ADU rents

Wait or advocate if...

• Your state doesn't yet permit ADUs by right
• Your local jurisdiction is actively considering ADU legislation
• Your HOA restrictions preclude ADU builds

The quiet part.

The ADU-permission map is changing faster than any other US zoning category. States that were restrictive in 2022 are permissive in 2026. The trendline is clear: by 2030 the majority of remaining restrictive states will have some form of ADU-permission legislation.

If your state is currently restrictive, watch local advocacy efforts. Boulder, CO passed by-right ADU rules in 2023 after 3 years of advocacy; Denver followed in 2024. The permission is coming to most metros.

Related guides

• ADU vs. Tiny Home Comparison (2026) — the small-second-dwelling question
• Multi-Generational Living: ADU Design Guide — the multi-gen compound
• ADU Cost, Financing & Return Analysis — the financial picture

The waitlist is open

The PERCH marketplace opens with ADU builders serving by-right and non-by-right jurisdictions. The Financing Finder sorts your specific state + parcel into the right loan structure. Eight questions.

38 states down. 12 to go. Check your specific city regardless of your state's status. The permission map moves fast.