title
Conduct a noticed Public Hearing to consider Zone Text Amendment ZT-26-02, which would amend Chapter 28 (Zoning Regulations) of the Solano County Code to revise and update sections pertaining to accessory dwelling units (ADUs) and junior accessory dwelling units (JADUs) to ensure consistency with State law; the project is exempt from the California Environmental Quality Act (CEQA) pursuant to Public Resources Code Section 21080.17 and CEQA Guidelines Section 15061(b)(3).
body
Published Notice Required? Yes _X_ No ____
Public Hearing Required? Yes _X_ No ____
RECOMMENDATION:
The Department of Resource Management recommends the Planning Commission:
1. Conduct a noticed public hearing to consider Zone Text Amendment No. ZT-26-02; and
2. Adopt a resolution recommending that the Board of Supervisors adopt the proposed ordinance Zone Text Amendment No. ZT-26-02 amending Chapter 28 amending Chapter 28 of the Solano County Code to revise and update sections pertaining to accessory dwelling units (ADUs) and junior accessory dwelling units (JADUs) to ensure consistency with State law (Attachment A).
SUMMARY:
The matter before the Planning Commission involves proposed amendments to Chapter 28 of the Solano County Code (Zoning Regulations) to revise and update Section 28.72.10(B)(2) pertaining to accessory dwelling units (ADUs) and junior accessory dwelling units (JADUs) in the unincorporated area of Solano County. The updates align County regulations with current state law (Government Code Section 66310 et seq.), clarify the types and locations of ADUs permitted by right, clarify ministerial approval standards for ADUs, update development standards for size, height, setbacks, and parking, and include other revisions intended to eliminate ambiguities, promote internal consistency, and implement the General Plan’s Housing Element Program E.3 which requires the county to amend the County’s Zoning Ordinance to be consistent with the latest state legislation related to ADUs.
DISCUSSION:
Overview
Accessory Dwelling Units (ADUs) are residential structures allowed incidental to a primary dwelling. They can be detached or attached to the primary dwelling. Junior Accessory Dwelling Units (JADUs) are smaller units created from the conversion of the primary dwelling's existing space, such as a garage. ADUs and JADUs are innovative and effective options for adding much-needed housing in Solano County. They provide numerous benefits, including affordability through the elimination of costs for land acquisition and major infrastructure installation. They also provide homeowners with potential rental income and allow multigenerational families to live near one another while maintaining privacy. Solano County has identified ADUs as a key strategy to achieve affordability requirements set by the state for new housing. The Association of Bay Area Governments (ABAG) found through recent surveys that within the Bay Area 30% of ADUs are occupied by people with very low incomes, 30% by those with low incomes, and 30% by those with moderate incomes for the area. Under the current Regional Housing Needs Assessment set by the state, unincorporated Solano County must build 315 units of varying income levels. In 2025 alone, wood-framed ADUs represented 35% of the issued housing permits for housing. Wood-framed single-family homes comprised 45% of the housing permits issued.
Due to their importance, state law continues to evolve, often reducing regulations that a local agency can apply, to promote more development of ADUs. Solano County's existing ADU regulations were last updated in 2020 and are no longer fully consistent with current state law. Since 2020, the California Legislature has enacted multiple bills amending Government Code Section 66310 et seq., imposing new requirements on local jurisdictions and further limiting local authority to regulate ADUs and JADUs. As a result, the County has been defaulting to state standards in circumstances where the existing County Code conflicts with state law, creating ambiguity for applicants and staff alike. Additionally, the 2023-2031 Housing Element of the General Plan obligates the County to bring its zoning regulations into compliance with current state ADU law through Housing Element Program E.3 which requires that the county amend the County’s Zoning Ordinance to be consistent with the latest state legislation related to ADUs. The proposed amendments replace the existing section in its entirety with regulations that are fully consistent with state law and apply to residential and mixed-use zoning districts only.
Current Regulations Proposed to Remain
Core elements of the existing Section 28.72.10(B)(2) remain in the proposed ordinance:
• ADUs and JADUs continue to be permitted in residential and mixed-use zoning districts.
• The four-foot minimum side and rear setback standard for new detached ADUs.
• Size limits remain unchanged.
• The requirement that front yard landscaping for a detached ADU be consistent with that of the primary dwelling.
• For JADUs, the 500 sq. ft. maximum size, the efficiency kitchen requirement, the separate entrance requirement, and the prohibition on locating a JADU in a multifamily dwelling or accessory structure.
• The ministerial approval process for all qualifying ADUs and JADUs.
• The prohibition on requiring fire sprinklers when not required for the primary dwelling.
• The prohibition on separate sale or conveyance of ADUs and JADUs from the primary dwelling.
Summary of Changes:
Allowed ADU Types and Locations. The ordinance would clarify the types of ADUs permitted on residential and mixed-use parcels, including: (a) detached ADUs; (b) attached ADUs, including conversion of existing partially enclosed spaces; (c) ADUs created within the space of an existing single-family dwelling or accessory structure; and (d) junior accessory dwelling units (JADUs) contained entirely within an existing or proposed single-family dwelling. Attachment C provides a graphic representation of the different ways an ADU could be built. ADUs are permitted on any legal parcel in a residential or mixed-use zoning district that contains an existing or proposed single-family or multifamily dwelling.
State ADUs. Consistent with Government Code Section 66323, “State ADUs” are required to be approved ministerially upon submission of a complete building permit application, without a zoning clearance or other land use entitlement. State ADUs are not subject to the additional local development standards (size, setback, parking, and buildable lot coverage) except as specifically required by state law. Four categories of State ADUs are established:
• One ADU within the space of a single-family dwelling or existing accessory structure (with up to 150 sq. ft. expansion for ingress/egress)
• One new detached ADU (up to 800 sq. ft.) on a lot with a proposed or existing single-family dwelling
• ADUs within non-livable portions of existing multifamily dwelling structures (up to 25 percent of existing units, or at least one, whichever is greater)
• Detached ADUs on lots with existing multifamily dwellings (up to eight, not exceeding the number of existing units) or proposed multifamily dwellings (up to two)
Junior Accessory Dwelling Units (JADUs). The amendment updates JADU standards consistent with Government Code Section 66333 and 66323. One JADU is permitted per lot with an existing or proposed single-family dwelling. JADUs must:
• Be created entirely within the walls of the single-family dwelling (including attached garages)
• Be limited to 500 sq. ft. of interior livable space.
• Have an efficiency kitchen and a separate exterior entrance.
• Sanitation facilities may be separate from or shared with the primary dwelling
o If shared, an interior connection to the primary dwelling is required.
• A deed restriction must be recorded prior to construction for rental terms, prohibition of separate sales, and limiting size and attributes to ordinance standards.
Development Standards for Local ADUs. ADUs that do not qualify as State ADUs are subject to local development standards and are approved ministerially. County code allows for the development of one (1) local ADU. Attached ADUs may not exceed 50 percent of the primary dwelling’s livable space or 1,200 sq. ft. Detached ADUs in R-TC zones are limited to 850 sq. ft. (or 1,000 sq. ft. for units with more than one bedroom). Detached ADUs in R-R zones are limited to 1,500 sq. ft. The minimum size for any ADU or JADU is 150 sq. ft. of floor area. This remains unchanged from the existing ordinance for ADUs.
Application Processing and General Standards. The new ordinance establishes detailed application processing timelines and general operational requirements for all ADUs, including:
• Applications must be deemed complete or incomplete within 15 business days of receipt and approved or denied within 60 days of a complete application.
o Applications not acted upon within 60 days are deemed approved.
o Written denials must identify all deficiencies and available remedies, and applicants may appeal incomplete or denied determinations to the Planning Commission, which must issue a final determination within 60 business days of the appeal.
• Nonconforming zoning conditions, code violations, or unpermitted structures that do not present a public health and safety threat and are unrelated to the ADU construction may not be required to be corrected prior to the issuance of the ADU’s building permit.
• ADUs and JADUs may only be rented as long-term rentals (30 days or more) as defined by Section 28.01. Owner-occupancy is not required for a property with an ADU. Owner-occupancy is required for a JADU that shares sanitation facilities with the primary dwelling unless the owner is a governmental agency, land trust, or housing organization.
• ADUs under 750 sq. ft. and JADUs under 500 sq. ft. are exempt from impact fees. Impact fees for larger ADUs shall be proportionate to the primary dwelling’s square footage.
• ADUs and JADUs shall not be considered new residential uses for density, connection fees, or capacity charge purposes, and shall not be counted under any ordinance, policy, or program limiting residential growth.
• The ordinance now notes the maximum number of local and state ADUs allowed per residential property or mixed-use zoning district.
GENERAL PLAN CONSISTENCY
The proposed ordinance is consistent with the Solano County General Plan in that the amendments to the text of Solano County Zoning Regulations are compatible with the objectives, policies, general land uses, and programs specified in the plan. Specifically, the proposed amendments implement Housing Element Program E.3, which directs the County to amend its Zoning Regulations as necessary to be consistent with the latest state ADU law. The proposed ordinance does not alter prior regulations for intensity or location of development in the County.
ENVIRONMENTAL REVIEW
The proposed zone text amendment is exempt from the California Environmental Quality Act (CEQA) pursuant to two independent exemptions. First, the amendment is exempt under Public Resources Code Section 21080.17 because it serves to implement state ADU and JADU regulations (Government Code Section 66310 et seq.). Second, the amendment is exempt under CEQA Guidelines Section 15061(b)(3) (Common Sense Exemption) because the proposed project has no potential to cause a significant effect on the environment.
PUBLIC HEARING NOTICE
In accordance with Solano County Zoning Regulations and State law, notice of a public hearing was published at least 20 days before the scheduled hearing in the Fairfield Daily Republic (Attachment B). In addition, all persons requesting notice of the public hearing were mailed notices of the hearing.
RECOMMENDATION:
Staff recommend that the Planning Commission adopt a resolution recommending that the Board of Supervisors adopt the proposed ordinance (ZT-26-02) amending Chapter 28 (Zoning Regulations) of the Solano County Code to revise and update sections pertaining to accessory dwelling units (ADUs) and junior accessory dwelling units (JADUs) consistent with State law.
ATTACHMENTS:
A - Resolution with Draft Ordinance
B - Public Notice
C - ADU Graphics