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Report regarding proposed Zoning Text Amendments to Title 20 of the South San Francisco Municipal Code to update regulations pertaining to accessory dwelling units to comply with California state law, and determination that the proposed amendments are categorically exempt from the California Environmental Quality Act (CEQA). (Stephanie Skangos, Senior Planner)
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MOTION FOR THE COMMISSION TO ADOPT STAFF RECOMMENDATION:
(1) Move to adopt the Resolution determining the proposed updates to ADU regulations are exempt from CEQA and recommending that the City Council adopt an Ordinance amending Title 20 of the South San Francisco Municipal Code.
RECOMMENDATION
Recommendation
Staff recommends that the Planning Commission conduct a public hearing and take the following action:
1. Adopt the attached Resolution determining that the proposed Zoning Ordinance amendments do not require additional environmental review and is exempt from the California Environmental Quality Act (CEQA) and recommending that the City Council adopt an Ordinance updating regulations pertaining to accessory dwelling units in Title 20 (“Zoning”) of the South San Francisco Municipal Code.
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BACKGROUND/DISCUSSION
On May 21, 2026, the Planning Commission reviewed proposed updates to the City’s ADU Ordinance to bring it into compliance with the most current State law and recommended that the City Council adopt an Ordinance with the updates. The staff report from the May 21, 2026 Planning Commission meeting is attached as reference (Attachment B).
Prior to proceeding to City Council for review of the proposed changes, staff became aware of an updated interpretation of State law by the California Department of Housing and Community Development (HCD) regarding the total number of ADUs allowed on single- and multiple-unit lots. This interpretation is referenced in the latest version of the HCD Accessory Dwelling Unit Handbook, and increases the maximum number of total ADUs that may be located on both single-unit and multiple-unit lots. As such, the Planning Division and City Attorney are recommending that this interpretation be formalized in the City’s ADU Ordinance, to ensure continued consistency with State law.
A summary of the proposed changes related to the updated HCD interpretation only is included below, with the additional changes shown as highlighted red double underline and strikethrough. Staff has revised the previously reviewed draft ordinance to include these changes. The revised draft ordinance is attached to the associated Resolution as Exhibit A.
• Maximum Number of Units Allowed:
• For a single-unit lot with an existing or proposed single-unit dwelling, the number and type of allowed ADUs shall be:
§ One (1) detached ADU; AND
§ Either One (1) converted ADU (within the existing space of the home or an accessory structure) or one (1) attached ADU, but not both; AND
§ One (1) JADU; AND
§ One (1) attached, detached OR converted ADU (not exempt from local development standards)
• For a multiple-unit lot with an existing multiple-unit dwelling, the number and type of allowed ADUs shall be:
§ Up to eight (8) detached ADUs, not to exceed the number of existing residential units on the lot; AND
§ Converted ADUs up to 25% of the existing number of units or one, whichever is greater, within portions of an existing structure that are not used as livable space; AND
§ One (1) attached, detached OR converted ADU (not exempt from local development standards)
• For a multiple-unit lot with a proposed multiple-unit dwelling, the number and type of allowed ADUs shall be:
§ Up to two (2) detached ADUs; AND
§ One (1) attached, detached OR converted ADU (not exempt from local development standards)
In summary, the ordinance changes previously reviewed in May 2026 increased the total number of allowed ADUs on a single-unit lot from two (2) to three (3); the updated interpretation increases the total allowed ADUs by one (1) additional ADU, attached, detached or converted, for a resulting total of four (4) ADUs. The previously reviewed ordinance changes did not increase the total number of ADUs on a multiple-unit lot; the updated interpretation increases the total allowed ADUs by one (1) additional ADU, attached, detached or converted, resulting in various totals based on the number of existing or proposed residential units.
GENERAL PLAN CONSISTENCY ANALYSIS
The proposed Zoning Text Amendment is consistent with the City’s overall vision for providing a diversity of housing types responsive to household size, income, and age needs. Specifically, it will reinforce the below General Plan policies:
• Policy LU-3.1: Create affordable and workforce housing.
• Policy LU-3.3: Encourage diversity of housing types and sizes.
• Policy LU-3.4: Facilitate multi-generational housing.
• Policy LU-4.2: Encourage small-scale residential infill development.
None of the new or revised requirements for accessory dwelling units and junior accessory dwelling units will conflict with or impede achievement of any of the goals, policies, or land use designations established in the General Plan.
ENVIRONMENTAL REVIEW
The modifications to regulations pertaining to ADUs are statutorily exempt from CEQA pursuant to Section 21080.17 of the Public Resources Code, which states that local ordinances that are aimed at creating ADUs or JADUs are exempt from CEQA. Therefore, no further environmental review is required at this time.
CONCLUSION
Staff recommends that the Planning Commission conduct a public hearing and adopt the attached Resolution determining that the proposed Zoning Ordinance update does not require further environmental review and is exempt from CEQA, and recommending that the City Council adopt an Ordinance updating regulations pertaining to accessory dwelling units to Title 20 (“Zoning”) of the South San Francisco Municipal Code.
Attachments
1. Planning Commission Minutes, May 21, 2026
2. Planning Commission Staff Report, May 21, 2026
Exhibits to Associated Resolution (26-1764)
A. Draft Ordinance Implementing Zoning Text Amendments