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Solano County, CA Accessory Structures: ADU Rental Restrictions (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Minimum Term
30 days when ADU and JADU share a lot
Governing Section
Solano County Code § 28.72.10(B)(2)(p)(4)
ADU Size Cap
800 sq ft when paired with a JADU
JADU Footprint
Existing home footprint plus 150 sq ft
Separate Rule
JADUs alone also barred from short-term rental

Summary

When a Solano County lot carries both an accessory dwelling unit and a junior accessory dwelling unit, Section 28.72.10(B)(2)(p)(4) bars renting either unit for less than 30 days, closing off short-term or vacation-rental use of that combined pair even though a standalone ADU faces no such floor.

City-specific rules exist: Vallejo, and Vacaville have their own adu rental restrictions rules that differ from Solano County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

p. Accessory Dwelling Unit and Junior Accessory Dwelling Unit on Same Lot. An accessory dwelling unit and a junior accessory dwelling unit are not allowed on the same lot unless all of the following requirements are met:

(1) The accessory dwelling unit is detached from the primary dwelling and complies with all applicable development standards.

(2) The accessory dwelling unit does not exceed 800 square feet gross floor area.

(3) The junior accessory dwelling unit is entirely within the existing space of an existing single-family dwelling, or entirely within the proposed space of a proposed single-family dwelling; provided, that an existing single-family dwelling may be expanded by not more than 150 square feet for the sole purpose of accommodating ingress and egress for the junior accessory dwelling unit.

(4) When a lot is developed with both an accessory dwelling unit and a junior accessory dwelling unit, neither unit may be rented for a term of 30 days or less.

View official code

Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 1868, passed April 9, 2026).

Full Breakdown

Solano's zoning code allows an ADU and a JADU on the same lot only if four conditions in subsection (p) are all met. The accessory dwelling unit must be detached from the primary dwelling, hold no more than 800 square feet of gross floor area, and comply with every other applicable development standard; the junior accessory dwelling unit must sit entirely inside the existing or proposed footprint of the single-family home, with an allowance to expand that home by up to 150 square feet solely to add ingress and egress for the JADU.

The fourth condition, subsection (p)(4), is the rental restriction: neither the ADU nor the JADU on that lot may be rented for a term of 30 days or less once both units exist together. That 30-day floor mirrors, but is legally separate from, the standalone minimum-term rule in subsection (q)(4) that already bars any junior accessory dwelling unit from short-term rental on its own. The combined effect is that Solano County does not allow either half of an ADU/JADU pair to be marketed as a vacation rental or booked through short-term platforms; occupancy must run at least a full month.

A single, stand-alone ADU without a companion JADU is not subject to (p)(4), but subsection (i) still bars selling or otherwise conveying it separate from the primary dwelling, so the unit stays tied to the parcel even when it can be rented.

Violations & Fines

Renting an ADU or JADU on a combined-unit lot for stays under 30 days violates Section 28.72.10(B)(2)(p)(4) and can trigger code enforcement through the Department of Resource Management, including a notice to cure and the county's administrative penalty process under Chapter 10; a JADU rented short-term also independently violates the standalone minimum-term rule in subsection (q)(4).

Frequently Asked Questions

Can I rent out my ADU as a short-term rental in Solano County?
If your lot has both an ADU and a JADU, no: Section 28.72.10(B)(2)(p)(4) says "neither unit may be rented for a term of 30 days or less." A standalone ADU without a JADU on the lot isn't subject to that particular 30-day floor, though it can't be sold separately from the primary dwelling.
Does the same rule apply to junior accessory dwelling units by themselves?
Yes, independently. Subsection (q)(4) of the same section bars any JADU from being "rented for a term of 30 days or less," regardless of whether an ADU is also on the property.
What size can the ADU be if I also build a JADU?
Section 28.72.10(B)(2)(p)(2) caps a detached ADU sharing a lot with a JADU at 800 square feet of gross floor area, and the JADU must sit entirely within the existing single-family home's footprint, with only up to 150 additional square feet allowed for a separate entrance.

Sources & Official References

Other rules in Solano County

All Solano County rules

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