West Sacramento, CA Accessory Structures: ADU Rules (2026)

Even if requirements such as floor area ratio, proportionality (i.e. 50% threshold) to the existing or proposed primary dwelling unit's floor area, or other zoning standards cannot be met, the city must still allow an 850 square foot unit with setbacks of four feet from side and rear property lines, and up to the maximum building height permitted by the underlying zoning district.

B. Primary Dwelling Unit Required. The lot shall contain an existing detached single-unit dwelling at the time an application for an accessory dwelling unit is submitted, or the application for the accessory dwelling unit may be made in conjunction with the development of the primary dwelling. For ADUs in multi-family dwellings see subsection C below.

C. Number of Units. No more than one accessory dwelling unit and one junior accessory unit shall be permitted on any one lot. If the lot has an existing multifamily unit building then multiple ADUs are allowed in portions of existing multifamily dwelling structures that are not used as livable space, including, but not limited to, storage rooms, boiler rooms, passageways, attics, basements, or garages. Two detached ADUs can be added on a lot that has an existing multifamily dwelling.

D. Floor Area. The allowable square footage is 850 square feet for a one-bedroom ADU and 1,000 for an ADU over one bedroom. Lots larger than one acre can continue to have an ADU up to 1,200 square feet. The Junior ADU maximum square footage is 500 square feet.