Tiburon planning commission approves rewrite of ADU rules, keeps courtesy notice

The Town of Tiburon Planning Commission on Dec. 11 approved a resolution to repeal and replace chapter 16-52.100 of the municipal code, updating local rules for accessory dwelling units (ADUs) and junior ADUs (JADUs) to reflect state law changes and to clarify permitting procedures.

Staff said the update implements changes to state ADU laws enacted since June 2023 and reorganizes the chapter to make requirements easier to read for applicants. Savannah Van Aken, associate planner, told commissioners the draft replaces the chapter to: update zones allowing JADUs, revise permitting procedures and objective standards, adjust height and parking exceptions to track state law, clarify where multiple ADUs can be sited, clarify JADU bathroom and entrance requirements, update tree-removal standards to be objective, and remove the ordinance requirement to send a courtesy notice to neighbors because approvals are ministerial and not appealable.

Commissioners and staff discussed several specific changes and a set of clarifying edits the commission asked staff to incorporate before finalizing the text. Areas discussed at length included the courtesy-notice provision, JADU bathroom requirements, explicit examples of projects requiring design review (including roof decks), the parking footnote language, and a wording correction for a creek-related subsection. Commissioners also raised minor typographical and consistency edits for definitions and cross-references.

Several commissioners expressed concern that removing the courtesy notice would increase public confusion and reduce transparency. Commissioner Tsai and others argued that, even though ADU approvals are ministerial under state law and not appealable, continuing to send a courtesy notice can educate neighbors that the change stems from state law and may encourage others to consider ADUs. Staff said the notices consume significant staff time and cause confusion because recipients sometimes expect a discretionary hearing when none is available. Staff also said they already include language in notices stating the action is ministerial and required by state law.

After discussion the commission approved the resolution with the following edits, as read into the motion: revise the multifamily definition to be consistent across the code; list roof decks explicitly as examples of work that require design review (move to subsection 10.a); change the creek-section title and text to use a single, consistent term (“creek” rather than “creek bed”); clarify the half-mile phrasing and other small wording consistency items; revise the parking footnote to read that parking may be provided on a driveway if desired and is not required; remove an outdated government-code citation; and retain the courtesy-notice requirement but strengthen the notice language to explain that ADU provisions are mandated by state law and that ministerial approvals are not appealable.

The motion to adopt the resolution with those changes carried unanimously. Commissioners present who voted in favor: Chair Williams, Commissioner Tsai, Commissioner D'Feaver and Commissioner Woodward (4–0). Vice Chair O'Mear was absent.

The revised ordinance will next proceed through the town’s adoption process as required by local procedure.