California's governor announced the signing of a housing bill package on September 29, 2026. Two measures matter directly to owners considering accessory dwelling units (ADUs): AB 956 changes the state-law approval pathway for detached units, and SB 1117 changes how some ADU impact fees are calculated.
Under AB 956, a local agency must ministerially approve up to two detached, newly built ADUs on a lot with an existing or proposed single-family home when the statutory conditions are met. The bill allows specified size, height and setback limits. It also says a local agency need not approve a junior ADU on a lot where two detached ADUs have been built under this provision.
For up to two ADUs on a lot, SB 1117 says an impact fee for an ADU larger than 750 square feet is proportional to the primary home's area and applies only to the area above 750 square feet. This rule concerns impact fees; utility connection or capacity charges are separate.
Before changing a project plan
- Check the lot, drawings and permit pathway with the local agency, including when the signed laws become operative.
- Request an itemized fee estimate rather than assuming every project gets the same savings.
- Plan the rental model carefully: AB 956's amended section requires rentals of ADUs created under it to last longer than 30 days.
Sources: Governor's signing announcement, September 29, 2026 — https://www.gov.ca.gov/2026/09/29/governor-newsom-signs-housing-legislation-cementing-californias-record-progress-to-reduce-unsheltered-homelessness-and-build-more-homes/ ; AB 956 enrolled text — https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202520260AB956 ; SB 1117 enrolled text — https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202520260SB1117 . Checked September 30, 2026.
