Springfield, OR Environmental Rules: Stormwater Management (2026)

Springfield Development Code 4.3.110 sets the City's stormwater management standard for triggered development within Development and Public Works jurisdiction. Section (B) applies the rule to any project that creates or replaces 5,000 square feet or more of impervious surface, disturbs one acre or more of the development area, or generates peak flows exceeding 0.5 cubic feet per second. Section (C)(1) requires the Stormwater Study and the structural control design to be prepared and stamped by an Oregon licensed engineer. Developers choose between two performance paths under (C)(2): the Site Performance Standard, routing the first 1.4 inches of rainfall from each storm to controls that fully infiltrate, evapotranspirate, or reuse it onsite with no discharge, or the alternative Treatment Standard, treating that same first 1.4 inches to remove at least 80 percent of total suspended solids under (D)(3)(b)(ii), reviewed through a Type 2 (or Type 3, where the underlying development already needs Type 3) process because the applicant must show the Site Performance Standard is technically infeasible due to shallow bedrock, high groundwater, soil instability, or similar site constraints.

Section (C)(3) bars any stormwater system from connecting to or discharging into a public or private sanitary sewer. Permeable pavement may offset impervious area but cannot itself treat runoff from other surfaces, and underground injection wells need Department of Environmental Quality approval. High-risk uses such as fuel dispensing facilities, bulk outdoor storage, and vehicle washing facilities face added source-control standards under Appendix H, and rooftop equipment needs secondary containment to keep leaks out of the stormwater system.