932 official sources · verified July 2026
Find the ADU rules
for your city.
Every city, county, and state writes its own accessory dwelling unit rules, scattered across zoning PDFs and planning sites. ADU Rulebook puts the official sources in one searchable place.
410
cities & counties
41
states covered
932
official links
Coverage map
One map. Every rule we track.
ADU law is a patchwork: state statutes, county codes, city ordinances. The map shows where our coverage is deepest, and every state links straight into its directory.
- California120 jurisdictions + statewide law
- Maryland76 jurisdictions + statewide law
- Florida36 jurisdictions + statewide law
How it works
From “can I build?” to breaking ground
Look up your city
Search any of our covered cities and counties. Land directly on your jurisdiction's official ADU rules: zoning codes, permit guides, planning department pages.
Read the actual rules
No paraphrasing, no stale summaries. Every link goes to the government source your permit reviewer will use, stamped with the date we last verified it.
Build with confidence
Use our guides to budget and finance the project, then get matched with local designers and builders when you're ready to move.
Learn
Guides for first-time builders
Built to stay current
Zoning changes. So do we.
The biggest problem with every ADU directory before this one: staleness. Rules get amended, pages move, PDFs vanish. The ADU Rulebook stamps every entry with the date it was last verified, and the community can flag anything that drifts.
Verified dates on everything
Every jurisdiction shows when its sources were last checked, with no silent rot.
Primary sources only
Government sites and municipal codes, not summaries of someone else's summary.
Community-corrected
Found a dead link or a new ordinance? Report it and we'll verify it against the official source.
FAQ
Common questions
What is an accessory dwelling unit (ADU)?
An ADU is a smaller, independent home on the same lot as a primary residence, with its own kitchen, bathroom, and entrance. They're also called granny flats, casitas, in-law units, and backyard cottages.
Why are ADU rules so hard to find?
ADUs are regulated at multiple levels at once: state law, county code, and city zoning ordinances, each published separately and updated on different schedules. The ADU Rulebook collects the official sources for each jurisdiction in one place.
Is the information on the ADU Rulebook legal advice?
No. The ADU Rulebook links to official government sources so you can read the actual rules, but zoning decisions are made by your local planning department. Always confirm with them before building.
My city isn't listed. Can I request it?
Yes. Use the Contribute page to request a city or submit a link to its official ADU rules, and we'll verify and add it.
Ready to build?
Planning an ADU?
Tell us about your project and we'll match you with vetted local designers and builders as we bring them online. No cost, no obligation.