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

Subsection G of § 9102.01.080 sets the fee rules for every ADU approved under either the building-permit-only track or the ADU-permit track. The first rule is a flat exemption: no impact fee is required for an ADU that is less than 750 square feet in size. The code defines an impact fee for this purpose as a fee under the Mitigation Fee Act (Gov. Code § 66000(b)) and a fee under the Quimby Act (Gov. Code § 66477). The definition expressly leaves out any connection fee or capacity charge for water or sewer service, so those utility charges are a separate question.

An ADU of 750 square feet or larger can be charged an impact fee, but only proportionately in relation to the square footage of the primary dwelling unit. The code's own example divides the floor area of the ADU by the floor area of the primary dwelling and applies that ratio to the fee charged for a new dwelling.

Utility fees follow a second set of rules. If an ADU is built together with a new single-family home, it needs its own utility connection directly to the utility, and the normal connection fee and capacity charge for a new dwelling apply. A converted ADU on a single-family lot created under the building-permit-only conversion scenario is not required to have a new or separate utility connection, and no connection fee or capacity charge is required. Every other ADU needs a new, separate connection for any utility the city provides. That connection carries a fee or charge proportionate to the burden on the water or sewer system, measured by floor area or by drainage-fixture unit values under the Uniform Plumbing Code, and the city's portion cannot exceed the reasonable cost of providing the service. Utilities the city does not provide follow the connection and fee requirements of the utility provider.

Separately, the city can charge a fee to reimburse the cost of processing an ADU permit, including the costs of adopting or amending its ADU ordinance. The director of community development determines that fee and the city council approves it by resolution.