Casper, WY Environmental Rules: Stormwater Management (2026)

Chapter 13.49, the Urban Stormwater Quality Management and Discharge Control Ordinance, bars discharging anything other than stormwater into the municipal storm drain system or a watercourse under Section 13.49.090, unless the discharge falls on the exempt list, which covers things like unpolluted foundation drains, air conditioning condensation, individual residential car washing and firefighting flows, or is separately authorized by a Wyoming Pollutant Discharge Elimination System (WYPDES) permit with the city's written approval. Section 13.49.100 separately bans illicit connections, including tying a sewage line into the storm drain system, whether the connection is new or predates the ordinance.

New development and redevelopment projects must incorporate best management practices from the city's 2004 Erosion and Sediment Control Best Management Practices Manual under Section 13.49.130, and construction or industrial dischargers must hold and comply with their own WYPDES permit under Section 13.49.120. The city manager administers the chapter under Section 13.49.050 and can inspect, sample and test under Sections 13.49.200 and 13.49.210. When a violation is found, Section 13.49.220 requires a written notice of violation setting a compliance deadline; if the deadline passes, Section 13.49.230 lets the city or its contractor enter the property and abate the violation at the owner's expense, with a right to appeal to a municipal court hearing examiner within ten days under Section 13.49.240.

Section 13.49.270 also declares any violating condition a public nuisance the city can abate directly. A straight violation of the chapter is a misdemeanor under Section 13.49.260, punished per the Chapter 1.28 general penalty, and Section 13.49.280 warns that the same conduct can separately trigger civil and criminal liability under the Federal Clean Water Act.