How We Research and Verify ADU Rules

Every city page on ADUByCity is written and maintained by the ADUByCity Team. We are not lawyers or a government agency. Our job is to read the official rules so you can start from an accurate summary, then confirm the details with your city before you apply.

Where the data comes from

• Each city's ADU ordinance in its municipal code, and the planning department's ADU page.
• City fee schedules and pre-approved ADU plan programs, where the city publishes them.
• California law (Government Code §§66310–66342) and the Department of Housing and Community Development (HCD) ADU Handbook, for the rules that apply in every city.
• Build costs and rents are estimates from published contractor pricing and local rental listings. They are ranges, not quotes.

What “last verified” means

The date on each city page is the last time we checked that city's size limits, height limits, setbacks, and official links against its current ordinance or ADU page. “Last updated” is the last time we changed something on the page. Cities amend their ordinances about once a year, so we re-check every city at least annually and flag pages that are more than a year old.

Statewide rules are kept in one place and were last reviewed on September 30, 2026. When the Legislature passes a new ADU bill, we update that summary and the California ADU law guide.

Corrections

If something on a city page is out of date, let us know and include a link to the city source. We fix confirmed errors and update the page's “last updated” date.

Key statewide sources

• HCD Accessory Dwelling Unit Handbook
• HCD: Accessory Dwelling Units
• California Government Code §§66310–66342 (ADU and JADU law)

ADUByCity provides general information, not legal, zoning, or construction advice.