Under The Clean Water Act (CWA), The Environmental Protection Agency (EPA) Established Pollution Control Programs Including The National Pollutant Discharge Elimination System (NPDES).

The NPDES stormwater permit system regulates stormwater discharges from three sources: municipal separate storm sewer systems (MS4s), construction activities, and industrial activities. SEMSWA, as a Phase II regulated MS4 operator under the Colorado Discharge Permit System (CDPS) Regulation 61.8(11) General Permit associated with MS4s, is required to implement control measures in our stormwater management program to reduce the amount of pollutants in stormwater discharges.

These program areas include:

• Public Involvement/Participation
• Illicit Discharge Detection and Elimination
• Construction Sites 
• Post-Construction Stormwater Management (New Development and Redevelopment)
• Pollution Prevention/Good Housekeeping for Municipal Operations

SEMSWA is committed to using an integrated approach to meet the requirements and intent of our MS4 stormwater permit. Currently, SEMSWA holds the MS4 Permit(s) for the City of Centennial, the Arapahoe County Water and Wastewater Authority, the East Cherry Creek Valley Water and Sanitation District, and the Inverness Water and Sanitation District.  A Program Description Document (PDD) is available to the public for review and comment.