https://www.colorado-stormwater-council.org/stormwater-101-illicit-discharges/
Stormwater 101: Illicit Discharges - Colorado Stormwater Council
Jul 15, 2025 - What are Illicit Discharges? Illicit Discharges are anything other than rain or snow melt that enters storm sewers such as dirt, oil, chemicals, concrete, and...
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