Hercules, CA Accessory Structures: ADU Owner Occupancy (2026)
Key Facts
- JADUs allowed per lot
- 1
- Occupancy rule
- Owner must live in JADU or main house
- Exempt owners
- Gov't agency, land trust, housing org
- Deed restriction required
- Gov't Code § 27281.5 compliant
- Default penalty
- Up to $1,000 fine / 6 months (Sec. 1-4.01)
Summary
Hercules allows one junior accessory dwelling unit per single-family lot, but the property owner must live in either the JADU or the remaining part of the house. Government agencies, land trusts and housing organizations are exempt from that occupancy rule.
Junior Accessory Dwelling Units (JADUs). One JADU may be built per residential lot zoned for single-family residences with an existing or proposed single-family residence. The owner of the existing or proposed single-family residence must reside in the JADU or the remaining portion of the single-family residence unless owner is a governmental agency, land trust, or housing organization.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 555, passed March 25, 2025).
Full Breakdown
320(11) of the Hercules Municipal Code caps JADUs at one per residential lot zoned for single-family use with an existing or proposed single-family residence, and ties that approval to owner-occupancy: the owner of the residence must reside in the JADU itself or in the remaining portion of the single-family home, unless the owner is a governmental agency, land trust, or housing organization. 5 before the City issues a building permit for a JADU. 320 and state ADU law. A JADU must include at minimum an efficiency kitchen with a cooking facility, food preparation counter, and storage cabinets sized proportionately to the unit.
JADUs are exempt from the ADU parking standards in subsection (8), though the owner may add parking voluntarily, and a JADU is never treated as a separate or new dwelling unit for water, sewer, or power connection purposes, so no new utility connection or connection fee applies. The Community Development Director reviews JADU applications ministerially alongside the standard 60-day ADU permit timeline set out in subsection (2) of the same section.
Violations & Fines
The Hercules Municipal Code has no separate penalty clause inside Section 13-35.320, so a JADU built or occupied in violation of the owner-occupancy or deed-restriction requirements falls under the citywide default in Section 1-4.01: an unspecified Code violation is a misdemeanor punishable by up to a $1,000 fine, up to six months in jail, or both, with each day of continuing violation treated as a separate offense. The City may also pursue civil remedies or administrative citations under Section 1-4.02 in lieu of criminal prosecution.
Frequently Asked Questions
Can I rent out my whole house and live in the JADU instead?
Does the owner-occupancy rule apply if a nonprofit owns the property?
What paperwork does the City require before permitting a JADU?
Sources & Official References
Other rules in Hercules
California rules heatmap·Compare Hercules to another location·View the California accessory structures overview
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ADU Owner Occupancy in Nearby Cities
How other cities in Contra Costa County handle adu owner occupancy.