Salt Lake County, UT Environmental Rules: Stormwater Management (2026)

Salt Lake County operates a Municipal Separate Storm Sewer System (MS4) regulated under the Utah Pollutant Discharge Elimination System (UPDES) general permit issued by the Utah Division of Water Quality within UDEQ. The County Code Title 17 and Flood Control Engineering Division implement federally required stormwater programs. Key prohibitions include discharging any non-stormwater into storm drains, streets, gutters, or ditches; discharges include vehicle wash water (except de minimis personal car washing), concrete washout, paint rinse water, landscape fertilizer runoff, sanitary waste, cooking grease, pool water without dechlorination, and construction sediment. Construction sites disturbing one acre or more are required to obtain UPDES Construction General Permit coverage from the state, prepare a Stormwater Pollution Prevention Plan (SWPPP), install and maintain Best Management Practices (BMPs) such as silt fence, inlet protection, stabilized construction entrances, and concrete washout containment. The County also requires site-specific erosion control plans for smaller projects that drain directly to the Jordan River, Mill Creek, Big and Little Cottonwood Creek, or other impaired waters. Post-construction stormwater treatment is required for new and redevelopment projects disturbing half an acre or more, typically using bioretention, permeable pavement, detention with water quality treatment, or equivalent measures to capture the 80th percentile storm event. Illicit discharge complaints are investigated by the Flood Control Engineering Division. Violations are subject to administrative penalties up to 5,000 dollars per day along with cleanup cost recovery.