Union City, CA Accessory Structures: ADU Rules (2026)
ADU rules in Union City, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Review type
- Ministerial, no hearing
- Timeline
- 60-day approval deadline
- Missed deadline
- Application deemed approved
- Denials
- Written defect list required
Summary
Union City must approve or deny a complete ADU or JADU permit application within 60 days and cannot require a hearing or discretionary review: miss the deadline and the application is automatically approved.
A permit application for an ADU and/or JADU shall be processed ministerially, without discretionary review or a hearing.
2. Review Period.
a. Developed Lot. If there is an existing single-family or multifamily dwelling on a lot, a permit application for an ADU and/or JADU shall either be denied or approved within 60 days of receipt of a complete application.
b. Undeveloped Lot. If a permit application to create or serve an ADU and/or JADU is submitted with a permit application to create a new single-family or multifamily dwelling on a lot, the City may delay approving or denying the permit application for the ADU and/or JADU until the City approves or denies the permit application to create the new single-family or multifamily dwelling; however, the application to create or serve the ADU and/or JADU shall be considered without discretionary review or hearing. If the applicant requests a delay, the 60-day time period shall be tolled for the period of the delay.
3. Deemed Approved. If a complete application is not approved or denied within 60 days of receipt of a complete application, the application shall be deemed approved.
4. Denied Applications. If an application for an ADU and/or JADU is denied within 60 days of receipt of a complete application, the City shall return in writing a full set of comments to the applicant with a list of items that are defective or deficient and a description of how the application can be remedied.
5.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4940544; v16 updated 2026-06-23).
Full Breakdown
Union City processes ADU and JADU permits ministerially under Union City Municipal Code § 18.34.020: no discretionary review, no public hearing, and no planning commission approval required. The City must approve or deny a complete application within 60 days (tolled on request when it's paired with a new single-family or multifamily construction permit); if the City misses that deadline, the application is automatically deemed approved. Denials must come with a written list of specific defects and how to cure them, and the City cannot deny an application over unrelated pre-existing nonconforming conditions, code violations, or unpermitted structures that pose no public-safety threat.
Violations & Fines
None: this section sets an approval deadline binding on the City, not a penalty on applicants; a missed 60-day deadline results in automatic deemed approval of the ADU/JADU permit.
Frequently Asked Questions
Can Union City require a public hearing for an ADU permit?
What happens if Union City misses the 60-day ADU review deadline?
Sources & Official References
Other rules in Union City
How Union City compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Union City to another location·View the California accessory structures overview
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ADU Rules in Nearby Cities
How other cities in Alameda County handle adu rules.