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

62, every new residential project pays a parks and recreation development impact fee before it can get a building permit signoff. 080; for a multifamily unit it is $10,158, also annually adjusted. 040(A)(1)(b) and (A)(2)(b) carve out ADUs specifically: an ADU built on a single-family lot is charged "the maximum fee allowed by law, but in no event more than" the full single-family unit fee, and an ADU on a multifamily property is capped the same way against the multifamily fee. 2(f), which limits impact fees on ADUs under 750 square feet to zero and prorates fees for larger ADUs against the fee that would apply to the primary dwelling.

040(C) also credits any dwelling units being demolished as part of the same project against the new fee owed, so a homeowner converting an existing structure into an ADU does not pay twice for square footage the city already counted. The fee is collected by the city's building/planning department before final building permit approval, or before final inspection or certificate of occupancy if state law requires that later timing. 040(B)(1).