Stockton, CA Accessory Structures: ADU Impact Fees (2026)

310(I)(2), the Fees provision for accessory dwelling units, splits fee treatment into three parts. Connection fees or capacity charges for utilities like water and sewer cannot be imposed on an ADU as if it were a new residential use, unless the ADU is built alongside a brand-new single-unit dwelling, and this connection-fee break applies only to ADUs, not JADUs. For impact fees specifically, the code states they shall not be imposed on an ADU under 750 square feet of floor area or on any JADU with 500 square feet or less of interior floor area; for every other, larger ADU, impact fees are charged proportionate to the square footage of the primary dwelling unit rather than as a flat new-unit fee.

A third break covers school mitigation fees: an ADU or JADU with less than 500 square feet of interior livable space is exempt from those fees entirely under California Education Code Section 17620(a)(1)(C). 3(b). Separately, all ADUs must connect to public water, electric, and sewer utilities under subsection (I)(3), and the city may require a direct utility connection or proof that an existing well and septic system can handle the added demand, unless the ADU was built with a new primary dwelling.