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

110 governs every fee tied to building an ADU in Vista. Subsection A keeps plan check and building inspection fees in place for every ADU and junior ADU regardless of size, since those cover the Building Division's cost of reviewing and inspecting the structure. Subsection B is the exemption: development impact fees do not apply at all to an ADU of 750 square feet or less, and only kick in above that threshold, at which point they are calculated proportionately to the square footage of the primary residence rather than as a flat citywide rate.

Subsection C layers in a separate rule for school districts, which may charge their own school impact fees once an ADU reaches 500 square feet, independent of the city's 750-square-foot threshold. Subsection D requires the property owner to pay utility connection fees and capacity charges for water and sewer service when the ADU is built alongside a new single-family home, sized proportionately to the added burden on those systems. Subsection E goes further than the base exemption: all development impact fees for an ADU of any size are waived for ten years if the unit is occupied by an eligible household, defined as a lower-income household at or below 80 percent of the San Diego County median income, or a family member or caregiver providing regular care to someone in the primary residence.

That waiver requires the owner to record a regulatory agreement or deed restriction approved by the City Attorney before the tenant moves in, and the unit must be tracked toward the City's regional housing needs assessment.