Rohnert Park, CA Accessory Structures: ADU Impact Fees (2026)

040(H) sets the city's connection, capacity and impact fee rules for ADUs and JADUs separately from its general design and setback standards. Subsection (H)(1) allows a new, separate or upgraded water or sewer connection only where site-specific conditions actually require one, and lets the city calculate connection fees or capacity charges proportionate to the ADU's burden, using square footage, drainage fixture unit values under the Uniform Plumbing Code, or another method that reasonably estimates the ADU's proportional impact, rather than charging the full new-connection rate.

Subsection (H)(2) requires the applicant to show the city engineer that adequate water and sewer service already exists before a certificate of occupancy issues. Subsection (H)(3) states that a JADU is never treated as a separate or new dwelling unit for water, sewer or power purposes, including connection fees, and an ADU is not treated as a new residential use for connection fee or capacity charge purposes unless it is built together with a new single-family dwelling. The headline exemption sits in (H)(4): no impact fee at all may be assessed on an ADU under 750 square feet or on any JADU regardless of size, and once an ADU reaches 750 square feet or larger, the impact fee charged must be proportional to the ADU's square footage relative to the primary dwelling, not a flat new-unit fee. Subsection (H)(1) also carves out an exception for ADUs built within an existing single-family dwelling, which typically need no new utility connection at all.