San Mateo County, CA Accessory Structures: ADU Owner Occupancy (2026)
Key Facts
- Scope
- Unincorporated county only; JADUs
- Owner-occupancy required
- Yes, one unit on parcel
- Enforcement tool
- Recorded deed restriction
- Section
- § 8.392.080(5)
Summary
Unincorporated San Mateo County requires the parcel owner to live in one unit whenever a junior accessory dwelling unit is built, secured by a recorded deed restriction.
Owner Occupancy. The owner(s) of the parcel on which a junior accessory dwelling unit is proposed shall be required to occupy one (1) of the units on the parcel. The owner(s) shall be required to record a deed restriction enforcing this requirement, which shall run with the land, and which shall be provided to the Planning and Building Department. The deed restriction shall also include a prohibition on the sale of the junior accessory dwelling unit separate from the sale of the single-family residence, including a statement that the deed restriction may be enforced against future purchasers.
6. Parking. No additional parking shall be required for the creatin of a junior accessory dwelling unit.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 47).
Full Breakdown
Section 8.392.080(5) requires the owner(s) of a parcel with a proposed junior accessory dwelling unit to occupy one of the units on the parcel, and to record a deed restriction with the Planning and Building Department enforcing that requirement so it runs with the land. The deed restriction must also bar selling the JADU separately from the single-family residence, enforceable against future purchasers. Applies to JADUs in the unincorporated county only.
Violations & Fines
Failing to record the required deed restriction or violating the owner-occupancy covenant is enforceable against the property through the recorded restriction and can jeopardize the JADU's approved status.
Frequently Asked Questions
Must I live on the property to build a junior ADU?
Can I sell the JADU separately from the house later?
Sources & Official References
Other rules in San Mateo County
California rules heatmap·Compare San Mateo County to another location·View the California accessory structures overview
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