ADU Laws by State: What Changed in 2026
A dozen states updated their ADU laws in 2026. Here's a plain-English breakdown of what changed, what it means for homeowners, and which states are now the easiest to build in.
Why ADU Laws Are Changing So Fast
The United States is in the middle of a housing shortage. Legislators at the state level — frustrated with slow-moving local zoning boards — have started preempting local rules to allow more housing by right.
ADUs are the lowest-hanging fruit. They're small, they're built on existing lots, and they don't require new infrastructure. So states across the country are making them easier to build.
Here's what changed in 2026.
States That Passed New ADU Legislation in 2026
California
California's AB 976 took effect January 1, 2026, permanently eliminating the owner-occupancy requirement. Previously, a temporary exemption was set to expire — AB 976 made the change permanent.
What this means for you: You can now build and rent an ADU in California without living on the property, indefinitely.
Colorado
Colorado's HB 1152 went into full effect in 2026, requiring most municipalities to allow at least one ADU on single-family lots. Cities had until mid-2025 to update their zoning codes.
What this means for you: If you're in a Colorado city covered by the Growth Management Act, you now have a legal right to build an ADU.
Montana
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Montana passed SB 245 in 2025 and implementation took effect statewide in early 2026, requiring cities to allow ADUs on single-family lots and limiting impact fees.
What this means for you: Montana is now one of the more permissive states for ADU construction, even in smaller cities.
States to Watch in Late 2026
Several states have ADU bills in committee or moving toward passage:
- Arizona — HB 2192 would preempt local ADU restrictions statewide
- Nevada — AB 310 proposes impact fee waivers for ADUs under 800 sq ft
- North Carolina — Multiple bills targeting local zoning reform
What Still Varies at the City Level
Even in states with permissive ADU laws, cities can still regulate:
- Design standards — height, materials, appearance
- Short-term rental rules — some cities restrict Airbnb use of ADUs
- Utility connections — some cities require separate meters
Always check your city's specific ordinance before finalizing plans.
Bottom Line
The trend is clearly toward more permissive ADU laws nationwide. If your state hasn't passed legislation yet, it likely will in the next 2–3 years — making now a good time to start planning.
Use our state guides to see exactly what applies to your property today.