Can I build an ADU on my property?

Pick your state, your city if we cover it, what's on your lot now and what you'd like to build. The checker gathers what our state and city pages say about it, word for word, with links to the full pages and their official sources. Everything runs in your browser; nothing is sent anywhere.

This checker doesn't decide whether you can build. It shows the general rules. Your city's rules decide the details, and your lot's zoning and conditions matter too; check with your city's or county's planning department before you design or build.

Choose your state to see what we have for it.

How the checker works

Nothing new is written here. Every rule shown is copied from one of our state and city pages, each checked against official sources and independently audited. The full page has the source for every fact.
Your answers only sort the facts. The ones that mention your kind of project come first; the rest of the state's rules are one tap away.
Local rules come last but matter most. Cities and counties set sizes, setbacks, fees and design rules within what state law allows, and some areas have extra limits. Your planning department can tell you what applies to your lot.