Santa Rosa council introduces SB9-related zoning changes and debates ADU limits in wildfire- and narrow-street areas

Santa Rosa planning staff presented proposed zoning-code updates on Jan. 7, 2025, to implement new state laws including changes to accessory dwelling-unit rules and Senate Bill 9 (SB9) procedures. The Planning Commission and staff recommended text amendments to Title 20 to ensure local code alignment with recent state changes and to add an optional local restriction on ADUs in cases where property owners fully use SB9's two provisions.

What staff proposed: Planning staff said recent state laws require local code changes for ADUs, density bonus rules, shared parking agreements and general-plan/zoning coordination. The presentation described three ADU-related state changes: (1) permanent removal of the owner-occupancy deed restriction for ADUs; (2) a legalization pathway for existing unpermitted ADUs; and (3) allowing up to eight ADUs on multifamily properties (subject to existing unit counts).

SB9 and ADU interaction: SB9 allows either an urban lot split (two-lot subdivision) and/or a two-unit development on a single-family parcel. Staff explained that when property owners use both SB9 provisions on the same lot, state law allows additional ADUs but the city also has limited discretion to prohibit or limit the number of ADUs created under that combined scenario. Planning staff recommended an optional local rule restricting ADUs and JADUs on parcels that have been redeveloped under both SB9 provisions if the parcel is within the Wildland-Urban Interface (WUI) or fronts on streets narrower than a stated minimum. Planning said the rule aims to address safety, emergency access and on-street parking concerns.

Options and council debate: Staff outlined multiple policy choices ranging from (A) the recommendation to allow up to one ADU and one JADU on SB9-developed parcels outside the WUI with adequate street width, while limiting ADUs inside the WUI or on narrow streets; (B) status quo (allowing up to two ADUs and one JADU regardless of location); (C) citywide limit regardless of WUI/street width; and (D) complete prohibition of ADUs/JADUs on any parcel developed under both SB9 sections. Council members pressed staff and the fire marshal on how narrow-street criteria were set and whether the city could craft a more granular standard tied to lot frontage or lot size. Fire Marshal Paul Lowenthal explained the adopted street-width benchmarks were chosen to preserve unobstructed travel lanes and emergency access.

Council action and next steps: After public comment and extended council debate, the council voted to introduce an ordinance amending Title 20 consistent with staff recommendations, with a subsequent friendly amendment proposed and accepted to focus the restriction on WUI areas while preserving the status quo outside the WUI in certain language (council discussion and amendment details are recorded in the minutes). A roll-call vote on the motion to introduce the ordinance passed 4-3. Planning staff will submit the amended ordinance for final adoption and will also send the updated language to the State Department of Housing and Community Development for confirmation of state-law consistency.

Why it matters: The interplay between SB9 and ADU rules determines how many dwelling units a single-family parcel can accommodate; staff said councils can adopt targeted limits under state law but not prohibit ADUs in every circumstance. Council members expressed mixed views: some favored immediate local restrictions in wildfire-prone or narrow-street areas to protect safety, while others urged more data and asked staff to return with frontage- or lot-size-based refinements if the city needs to limit impacts.

Ending: Planning staff will move the ordinance through the formal adoption process and will coordinate with HCD and fire/public-works staff on maps and criteria for any WUI or street-width-based limitations. Council asked staff to monitor SB9 activity and return with evidence-based changes if the program produces significant neighborhood impacts.