San Ramon, CA Accessory Structures: ADU Rules (2026)

Section D4-39 of the San Ramon Zoning Ordinance implements California Government Code Chapter 13 of Division 1 of Title 7 (the state ADU law), and applies to every parcel in the city that has at least one existing or proposed dwelling unit. The section's stated purpose is to increase the supply and range of housing options, streamline small-scale infill development, minimize governmental constraints on ADU construction, and support the Housing Element's goal of adding units that are more affordable to San Ramon residents. Definitions used throughout the section, such as what counts as an ADU versus a junior accessory dwelling unit, are pulled directly from California Government Code Section 66313 et seq. rather than defined locally, so state law controls unit size, height and parking specifics.

The operative local step is procedural: before the Building Division will issue a building permit for an ADU or JADU, the applicant must first process and obtain a Zoning Clearance under Section D6-30, reviewed for compliance with Government Code Sections 66317 and 66335 et seq. Because the ordinance states that ADUs 'shall be allowed by-right (ministerially permitted) in any zone which allows for residential uses,' the Community Development Department cannot subject a code-compliant application to a discretionary hearing, public notice, or Planning Commission vote. That by-right treatment extends into mixed-use zoning districts that otherwise combine residential and non-residential land uses. Section D4-39 was adopted by Ordinance No. 522, Section 6, on December 12, 2023, and took effect January 11, 2024, replacing the city's prior discretionary ADU review track with the current ministerial process.