In violation of EPA's General Permit for Stormwater Discharges from Small Municipal Separate Storm Sewer Systems, Lawrence has failed to develop and implement a program to identify and eliminate illicit connections to the City's MS4, has failed to develop and enforce a regulatory mechanism for prohibiting illicit discharges, and has failed to develop a mechanism for controlling discharges from construction sites. Compliance with the NPDES Permit controlling the City's management of its sanitary sewers is similarly inadequate. A single NPDES permit authorizes discharges from the Greater Lawrence Sanitary District and its member communities, including Lawrence. Under that permit, the member communities must properly operate and maintain sewage collection systems tributary to the GLSD treatment plant. The City of Lawrence, has failed to meet its collection system obligations and EPA attributes sanitary sewer overflows (SSOs) to that failure. SSOs contribute high levels of pollutants, including heavy metals, toxics, oil and grease, solvents, nutrients, viruses, and bacteria to receiving waters, and are a significant cause of water quality violations within, and adjacent to, the City.