Union City, CA Accessory Structures: ADU Rules (2026)
Rules for building accessory dwelling units (granny flats, in-law suites) including size limits, parking requirements, and owner-occupancy rules.
Research in progress
We are currently verifying Union City's specific local ordinance for adu rules. In the meantime,California state law generally applies, and below you'll find guidance for finding the official rules and links to related Union City ordinances we've already verified.
California State Law Context
California state law provides the baseline framework for adu rules across all municipalities in the state. Individual cities like Union City may adopt additional local rules on top of state requirements, which is what makes checking your specific city ordinance important. For Union City 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 Union City ADU Rules rules
- Search for "Union City 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 rules rules live.
- Contact Union City 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.
ADU Rules in nearby cities
See how nearby Alameda County cities regulate adu rules: