EPA alleges that the Town of Canton failed to take required measures to detect and eliminate illicit discharges ( IDDE ) under EPAÂs NPDES General Permit for Storm Water Discharges from Small Municipal Separate Storm Sewer Systems ( Small MS4 Permit ). The Permit requires that permittees develop, implement and enforce a program to reduce the discharge of pollutants from municipal separate storm sewer systems to the maximum extent practicable and satisfy the water quality requirements of the Clean Water Act (ÂCWAÂ) and state water quality standards. This case is part of a comprehensive initiative to promote compliance with the Small MS4 Permit, and the PermitÂs IDDE requirementÂs in particular. Because of the particularly harmful nature of the pollutants in illicit discharges, Region 1 has made IDDE a priority for Small MS4 enforcement.