San Luis Obispo staff outline ADU, lot‑split changes to align city code with new state laws

San Luis Obispo City planning staff presented draft revisions to the city’s ADU and subdivision regulations that are intended to bring local code into compliance with recent state legislation and to simplify steps developers and homeowners must follow.

Planning staff said the draft, which the planning commission discussed and will be transmitted to City Council for hearings in early March, primarily updates outdated references and implements new state allowances for lot splits, multifamily ADUs and single‑family conversions. Staff emphasized the changes are meant to be iterative: they expect a second round of “cleanup” edits based on community feedback and state review.

The housing team summarized the main statutory references that motivated the rewrite, including bills the staff referenced in their presentation (Senate Bill 477, Senate Bill 1211, SB 450, SB 684, SB 9, SB 64 and SB 1123) and state law generally. Staff said the revisions split “lot‑split” procedures into major and minor categories to reflect recent state law, and they outlined thresholds and limits that come from the statutes rather than city policy.

Key technical points staff presented included: major urban lot splits will apply to many multifamily parcels and certain vacant single‑family parcels; resultant lots under state rules may be as small as 600 square feet (with a 1,200 square‑foot floor minimum in R‑1 zones); a subdivision processed ministerially must receive action within 60 days of a complete application under the state timeline; and lot splits cannot be used to separately sell existing dwelling units that the law requires remain with a parcel.

On ADUs, staff said the draft removes a local requirement that an ADU match the primary residence’s style and materials, removes the old one‑step‑then‑convert requirement (allowing certain conversions or additions to be reviewed in a single application), and implements the state’s new allowances for multiple accessory units on a single‑family lot. Staff described the general permitted configuration: a combination of detached ADUs, attached JADUs and conversions such that a typical single‑family lot could have up to three accessory units, subject to the size, setback and height rules of the underlying zone.

The presentation also addressed multifamily ADUs: existing units on a multifamily property can be converted in part to ADUs up to 25% of the building’s existing units, and a multifamily property may be allowed ADUs in parity with existing unit counts (for example a fourplex could qualify for up to four ADUs under the state provisions, subject to zoning standards).

Developers and participants pressed staff about how the new state rules will interact with local density calculations and whether a lot split followed by ADU approvals could be used to increase total buildable units beyond the underlying zone’s density. Staff said the state law in many cases constrains how lot splits and ADU allowances can be combined and that further policy choice remains with City Council where the state does not preempt local discretion. Staff committed to collecting the roundtable feedback and presenting possible city‑level options for council consideration in follow‑up code cleanups.

Next steps: staff said the consolidated draft will be before City Council in early March for initial hearings; staff will also send a compliance package to the state for review and will return to planning commission and council for further edits and policy questions such as short‑term rental limits for JADUs or whether the city will allow ADU/lot‑split combinations beyond the state minimums.