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

The rule sits in HMC § 3.36.080(E), part of Chapter 3.36, the development impact fee chapter adopted by Ordinance 461 in 2023. It reads that ADUs under 750 square feet are not charged development impact fees, that a larger ADU is charged proportionately to the square footage of the primary dwelling unit, and that ADUs remain subject to impact fees as allowed by Government Code Section 65852.2.

The fees themselves are set up in HMC § 3.36.030 in nine categories: law enforcement facilities; fire suppression facilities, vehicles and equipment; local circulation systems; regional circulation systems; local and regional flood control facilities; general facilities, vehicles and equipment; library facilities and collection; public use (community center) facilities; and park facilities development. The City Council fixes the dollar amounts in a fee resolution, and the chapter ties the calculation to the 2023 DIF Report dated August 28, 2023. Under HMC § 3.36.040 the fees are adjusted each April beginning April 2025 using the California Construction Cost Index.

Timing is set by HMC § 3.36.070. Except as Government Code Section 66007 requires, development impact fees are paid before issuance of the certificate of building occupancy. Fees are calculated by land use, evaluated by acreage, by dwelling unit or by square footage of construction.

Other exemptions in the same section help a homeowner adding space. A residential addition of less than 500 square feet of enclosed structure requiring a building permit pays no impact fee if the community development director finds no increase in the number of dwelling units, and at 500 square feet or more the fee applies to the footage above 499 square feet. A developer who believes the fee lacks a reasonable relationship to the impacts of the project can apply to the City Council for a reduction, adjustment or waiver under HMC § 3.36.110.