Accessory Structures in Marin County, CA (2026)

1 rule for unincorporated Marin County, California.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Marin County. If you live within an incorporated city, that city's own rules apply — see the city list below.

ADU Rules

Marin County Code §22.32.120 regulates ADUs in unincorporated areas. Detached and conversion ADUs under 800 square feet receive ministerial by-right approval. ADUs are allowed in single-family, multifamily, and mixed-use zones. The county currently extends its ADU permit fee waiver through December 31, 2026.

Marin County ADU Rules

Some Restrictions

Full ordinance details →Official source ↗

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