Bellingham, WA Accessory Structures: ADU Impact Fees (2026)

The creation of an accessory dwelling unit within an existing single-family structure or detached accessory building that was designed and built for human habitation under valid city building permits shall be exempt from the payment of multimodal transportation impact fees; provided, that: (a) the area being converted to an ADU was constructed as of May 21, 2018, and (b) the scope of the work does not include conversion of a garage or a concurrent or subsequent floor area addition to the primary residence or accessory building. In such cases, the impact fee for the ADU shall be assessed with the aforementioned scope of work.

C. Trip reduction credits to a project’s multimodal TIF assessment are available if a proposed development can show a reduction in p.m. peak hour person trips generated. Said reduction could be the result of transportation demand management strategies, linked trips, or other incentives that reduce p.m. peak hour person trips. Proposals will be considered and the credit applied to the project if approved by the city.

1. Specific trip reduction credits are available in Table 19.06.040(B) for urban village development in close proximity to WTA transit. Auto-oriented commercial and drive-through developments are not eligible.