Alameda County, CA Accessory Structures: ADU Permits (2026)
How to apply for an ADU building permit: application steps, plan-check requirements, review timelines, ministerial vs discretionary review, and which department to file with.
Research in progress
We are currently verifying Alameda County's specific local ordinance for adu permits. In the meantime,California state law generally applies, and below you'll find guidance for finding the official rules and links to related Alameda County ordinances we've already verified.
California State Law Context
California state law provides the baseline framework for adu permits across all municipalities in the state. Individual cities like Alameda County may adopt additional local rules on top of state requirements, which is what makes checking your specific city ordinance important. For Alameda County residents, the safest approach is to follow state law as a baseline and contact City Hall for any additional local requirements.
You can browse all California accessory structures to see how cities across the state regulate this topic.
How to find official Alameda County ADU Permits rules
- Search for "Alameda County CA municipal code" to find your city's online code portal (Municode, eCode360, or American Legal Publishing are the most common).
- Look for chapters covering accessory structures, zoning, nuisance, or property maintenance — that's where most adu permits rules live.
- Contact Alameda County City Hall's code enforcement, planning, or community development department for clarification.
- Check with your HOA if applicable — many HOAs have stricter rules than the city itself.
Other accessory structures verified for Alameda County
We've verified the following accessory structures for Alameda County: