Mendocino County, CA Accessory Structures: ADU Impact Fees (2026)

Sec. 030(C)(6) of the County Code addresses utility charges for junior ADUs specifically (not full-size ADUs, which are billed as normal per Sec. 030(A) and (B)). Under subsection (a), whether the JADU is built new or converted from existing space, the County cannot count it as a separate or new dwelling unit when calculating connection fees or County charges for water, sewer, power service, or impact fees; it is billed as part of the existing primary residence's service. Subsection (b) reinforces this by barring any requirement for a new or separate utility connection between the JADU and the utility provider, though the property owner may voluntarily install a submeter to track the unit's usage separately.

Subsection (c) is a savings clause: any utility charges or fees that do apply must still be consistent with state law, which caps what a local agency can charge an ADU under Government Code impact-fee provisions. This exemption only reaches JADUs, capped at 500 square feet and built within the footprint of an existing single-unit home under Sec. 020(C); a standard attached or detached ADU does not get this specific fee carve-out and is subject to the County's normal connection and impact fee schedule set by the Board of Supervisors.