Commerce City, CO Environmental Rules: Stormwater Management (2026)

Sec. 10-3000 of the Commerce City Revised Municipal Code states the purpose of Article III, Chapter 10: regulating nonstormwater discharges to the storm drainage system to control pollutants entering the municipal separate storm sewer system, or MS4, and to comply with the Colorado Discharge Permit System (CDPS) permit process; the article applies to all water and other substances entering the MS4 from any developed or undeveloped land unless the city manager grants an explicit exemption. Sec. 10-3002(a) sets the core prohibition: it is unlawful to discharge, or cause to be discharged, anything other than stormwater into the MS4 or any watercourse in the city.

Sec. 10-3002(b) carves out specific exemptions, including water line flushing, landscape irrigation, diverted stream flow, rising groundwater, foundation and footing drains that are not active dewatering systems, air conditioning condensation, noncommercial vehicle washing, natural riparian or wetland flows, swimming pool water with less than one ppm chlorine, emergency firefighting water, and any discharge covered by a CDPS permit, waiver or order. Sec. 10-3003 separately bans illicit connections to the MS4 outright, including connections made before the article took effect, regardless of whether they were lawful when built.

Sec. 10-3004 lets the city suspend MS4 discharge access without prior notice when a discharge presents an imminent danger to the environment or to public health, and Sec. 10-3007 requires every property owner, lessee or licensee along a watercourse to keep it free of trash, debris and other obstacles that would pollute it or block its flow. Sec. 10-3008 requires anyone responsible for a facility to report a known or suspected release of pollutants to the city manager no later than the next business day, confirmed in writing within three business days, and commercial or industrial dischargers must keep a written record of any release for at least three years.