Yuba City, CA Accessory Structures: ADU Impact Fees (2026)

5004(c)(9)a sets Yuba City's ADU fee floor at zero for the smallest units: no impact fees, as defined in Government Code Section 66324(c)(2), may be imposed on junior accessory dwelling units or on accessory dwelling units smaller than 750 square feet. That exemption covers the typical impact fees cities charge new residential construction for parks, traffic, and public facilities, and it applies automatically without a waiver application because the code states the fee cannot be imposed in the first place. Once an ADU reaches 750 square feet or larger, the city may charge impact fees, but only in proportion to the ADU's square footage relative to the primary dwelling unit, rather than at the flat rate applied to a new single-family home.

A 900-square-foot ADU added to a 1,800-square-foot house, for example, would be assessed impact fees calculated against roughly half the square footage the primary home would generate on its own, not the full new-construction fee schedule. Subsection (c)(9)b provides a second, separate protection for utility connection and capacity charges: an ADU is not treated as a new residential use for calculating water and sewer connection fees or capacity charges unless the ADU was built at the same time as a new single-family dwelling on the lot.

That means adding an ADU to an existing home does not by itself trigger new utility connection fees, only the proportional impact fee described above once the unit crosses the 750-square-foot threshold.