Cupertino council advances ADU ordinance revisions in first reading after lengthy debate

The Cupertino City Council conducted a first reading on Sept. 3 of an ordinance updating the city’s accessory dwelling unit (ADU) rules to conform to recent state law changes and feedback from the California Department of Housing and Community Development (HCD).

Staff said the city’s 2023 ADU ordinance became out of date after several state bills and reorganizations of government code sections went into effect in 2024–2025. Senior planner John Martier told the council the draft ordinance removes an earlier 1,200‑square‑foot cap on detached multifamily ADUs (HCD objected to that limit), revises how duplexes are treated under the city code, and clarifies rules on parking, permits and design standards for non‑streamlined ADUs.

The staff presentation noted two state statutes (cited in HCD’s April letter) that prompted the amendments and said the city had committed to reconcile its municipal code by Sept. 30, 2025.

Council members probed legal and policy details at length. Councilmember Fruin asked staff to repeat the provision that the planning commission had recommended removing — a draft requirement that all non‑streamlined detached ADUs match the principal dwelling’s siding and roofing materials — and staff confirmed the planning commission had recommended deleting that blanket requirement for most neighborhoods. Staff said objective design standards would remain in five special zoning districts (for example, Eichler neighborhoods and hillside zones) where explicit quantifiable standards already exist.

Councilmember Mohan and others pressed staff and the city attorney on whether the state government code forbids the city from setting any square‑foot limit for detached ADUs on multifamily parcels. Staff said HCD objected to the previously proposed 1,200‑square‑foot cap; city legal staff said HCD interprets the government code narrowly and that staff would seek clearer legal guidance about whether a different square‑foot or percentage cap would be permissible. Councilmembers requested that staff return before the second reading with a focused legal memo on that narrow question and on how any limits would affect the city’s housing element commitments.

There was extensive public comment and discussion about the broader effect of state ADU law: councilmember Wong noted the half‑mile “high transit” rule that allows greater height and relaxed parking requirements near frequent bus lines and warned the public that the half‑mile threshold can expand ADU rights in many neighborhoods.

After debate, the council conducted the first reading. The roll call and statements recorded during the meeting show Councilmember Fruin, Councilmember Mohan, Vice Mayor Moore and Mayor Chow voting in favor; Councilmember Wong recorded a “no” vote. Staff said the ordinance would return for a second reading and final adoption at a future council meeting (the item was scheduled for a second reading on Sept. 16 per staff). Councilmembers asked staff to include the planning commission’s design recommendations and requested staff provide the legal analysis on multifamily ADU size limits before the second reading.

Ending: The city advanced the update in a first reading but asked staff for targeted legal analysis on square‑foot limits for multifamily ADUs and for a revised ordinance incorporating the planning commission’s edits; a second reading is scheduled.