TO: Board of Supervisors
FROM: Brian D. Bordona, Director of Planning, Building and Environmental Services
REPORT BY: Trevor Hawkes, Supervising Planner
SUBJECT: Amendments to Titles 17 & 18 of the Napa County Code related to Urban Lot Splits and Two-Unit Development
RECOMMENDATION
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Introduction and intent to adopt an Ordinance of the Napa County Board of Supervisors, State of California, amending the Napa County Code Section 17.17.020 (Approval of Map) and 17.17.040 (Specific Adverse Impact) of Chapter 17.17 (Urban Lot Splits) of Title 17 Subdivisions) and Section 18.104.440 (Two Unit Developments) of Chapter 18.104 (Additional Zoning District Regulations) to bring the Code into alignment with current State law regarding Urban Lot Splits and Two-Unit Developments. (No Fiscal Impact; Discretionary)
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BACKGROUND
Proposed amendment to Napa County Code (NCC) sections due to current State housing law concerning Urban Lot Splits and Two-Unit Developments (Senate Bill 9 of 2021 and SB 450 of 2024).
PBES Staff, County Counsel and outside legal counsel have prepared the draft ordinance for Board consideration, amending NCC Chapter 18.104 (Two-unit Developments) and NCC Chapter 17.17 (Urban Lot Splits), due to amendments to the Government Code through legislative session 2025. All proposed amendments are intended to make the NCC current with the minimum required standards of state law. Please refer to the Executive Summary in Attachment C for a summary of modifications to each individual section.
Primarily the draft ordinance proposes amendments to the NCC due to Senate Bill 450 (2024). SB 450 made the following amendments to Government Code sections 65852.21 and 66411.7, the core statute governing Two-Unit Development and Urban Lot Splits, summarized as follows:
• Objective standards imposed on Urban Lot Splits and Two-Unit Development projects must generally also apply uniformly to the underlying single-family zone. Agencies cannot create special restrictive standards aimed only at Urban Lot Splits and Two-Unit Development projects unless they are more permissive.
• The County’s review must remain ministerial and generally be completed within 60 days of receipt of a complete application.
• Applications may not be denied based on generalized “physical environmental” impacts except under the narrower statutory health and safety exceptions.
• Department of Housing and Community Development (HCD) enforcement authority over Urban Lot Splits and Two-Unit Development compliance was strengthened.
• Local objective subdivision and design standards must be tied to parcel design/improvements and cannot effectively preclude Urban Lot Split projects.
The proposed amendments also addresses AB 1061, which narrowed historic district exemptions for Urban Lot Splits and Two-Unit Development projects.
Finally, revisions to NCC Sections 17.17.020, 17.17.040 and 18.104.440 are recommended to add clarity to the code in line with HCD’s recommended guidance on Urban Lot Splits and Two-Unit Developments.
Planning Commission Recommendation
On June 17, 2026, at a duly noticed public hearing, the Planning Commission recommended that the Board of Supervisors adopt the proposed ordinance. No changes to the proposed ordinance were recommended by the Planning Commission.
Additional Information
Today’s public hearing was noticed in the Napa Valley Register on Thursday, August 20, 2026. At the time of publishing, staff have not received any public comment.
Procedural Requirements
1. Open Public Hearing.
2. Staff report
3. Public comments
4. Close Public Hearing
5. Motion, second, discussion and vote on intention to adopt the Ordinance
FISCAL IMPACT
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Is there a Fiscal Impact? |
No |
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Is it Mandatory or Discretionary? |
Discretionary |
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Discretionary Justification: |
Current code is inconsistent with state law and may cause confusion in implementation. |
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Is the general fund affected? |
No |
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Future fiscal impact: |
None |
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Consequences if not approved: |
PBES Staff would have to rely on state law when reviewing Urban Lot Split and Two-Unit Development applications, which may create confusion and impede implementation |
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Additional Information |
County Strategic Initiatives: Build Healthy, Connected Communities; Champion Environmental Sustainability and Resilience; Preserve Napa County’s Agricultural Legacy |
ENVIRONMENTAL IMPACT
ENVIRONMENTAL DETERMINATION: Adoption of an ordinance to implement provisions of SB 9 (Government Code Sections 65852.21 and 66411.7) is not a project under CEQA. (Government Code Sections 65852.21(k) and 66411.7(n).)