Salem, OR Accessory Structures: ADU Impact Fees (2026)

Salem's System Development Charges fund transportation, parks, water, sewer, and stormwater capital improvements and are normally assessed on new dwelling units. The Salem City Council voted to waive SDCs on ADUs, which removes a major cost barrier (typical Oregon ADU SDCs in comparable cities range from roughly $11,000 to $20,000 per unit). The waiver applies to ADUs meeting the standards of SRC 700.007 and is administered by the Salem Public Works Department alongside the city's regular SDC schedule. Remaining ADU project costs in Salem include: (1) building permit fees under the Salem fee schedule, calculated on construction valuation under the Oregon Residential Specialty Code; (2) electrical permit fees under ORS 479 and OAR 918; (3) plumbing permit fees (gas piping is regulated as plumbing in Oregon); (4) mechanical permit fees for HVAC; (5) plan review fees, typically a fixed percentage of the building permit fee; (6) water and sewer connection fees if a separate meter or service is installed (sharing the existing tap with the principal dwelling avoids new connection charges); (7) the Oregon Construction Excise Tax under ORS 320.170-320.195 (administered statewide on permitted construction value); and (8) Marion County or Polk County recording fees on any deed restrictions or easements. The Salem-Keizer School District may apply a school Construction Excise Tax under ORS 320.170. Salem's Ready-Build pre-approved plan set for ADUs under 600 sq ft further reduces design costs.