Atherton planning commission recommends council adopt ADU code updates to align with state law

The Atherton Planning Commission on Sept. 24 voted unanimously to recommend that the City Council adopt amendments to the town’s accessory dwelling unit (ADU) ordinance to align local rules with recent state law changes and to clarify application-processing items staff said have arisen at the counter.

Town planner Britney Bennix summarized the package of proposed changes as technical and substantive updates tied to several 2024 state laws and to bills awaiting the governor’s signature. Staff said the amendments include renumbering references to sections of the California Government Code, clarifications that limit the town’s ability to impose certain design or objective-development standards on state-exempt ADUs, and updates to the town’s privacy-screening and landscape provisions so staff can encourage — but not require — some measures where state law preempts local rules.

Bennix reviewed other changes staff proposed: clarifying the town’s process for preapproved plan sets, aligning review timelines to state requirements for junior ADUs and certain ADU submittals, explaining that floor-area caps do not apply to conversions of existing buildings being converted to ADUs, and tightening language about the permitted relationship between detached garages and ADUs above garages so that the local code matches state intent.

Staff also discussed how recent and pending bills could affect local policy. Bennix said the package reflects four laws passed in 2024 and two measures pending gubernatorial action; she noted a separate, important bill (identified in the meeting as SB 79) would increase density limits near a regional rail station if the measure is signed and would have limited footprint within Atherton.

Commissioners asked clarifying questions about privacy fencing, lighting and how the town would implement the preapproved-plan option; staff said the proposal lets staff advocate for 8-foot screening as a voluntary mitigation where state law allows, but the town cannot impose an 8-foot requirement on state-exempt ADUs. Staff recommended the commission conduct the required public hearing and adopt a resolution recommending City Council approval. The commission voted to adopt the resolution and forward the ordinance amendments to council for consideration and further readings.