Rohnert Park, CA Accessory Structures: ADU Rules (2026)

040(A) makes an ADU or JADU a permitted use, without a discretionary hearing, on any lot zoned for single-family or multi-family residential use, including mixed-use zones, and subsection (C) requires the city to process a complete ADU application ministerially within sixty days when an existing dwelling is already on the lot. The maximum interior livable space under subsection (D)(2) is 850 square feet for an ADU with one bedroom or less and 1,000 square feet for an ADU with two or more bedrooms; an attached ADU larger than 800 square feet is additionally capped at fifty percent of the existing primary dwelling's floor area.

10 height limit for the primary dwelling if lower, for an ADU attached to the primary structure. Subsection (D)(7) backstops all of this: no standard, including setback, lot coverage, floor area ratio or size rules, may block construction of at least one 800-square-foot ADU meeting four-foot side and rear setbacks and the applicable height limit. No lot coverage requirement applies at all to an ADU of 800 square feet or less, and only one ADU plus one JADU is allowed per lot under the streamlining provisions in subsection (E).