The Del-Co Water Company’s primary sources of water are the Olentangy River, the O’Shaughnessy Reservoir, and the Alum Creek Reservoir. These surface water sources supply water to three of the system’s four water treatment plants: the Olentangy Plant, the Ralph E. Scott (Alum Creek) Plant, and the Timothy F. McNamara (Old State) Plant. Surface water is by its nature susceptible to contamination, and there are numerous potential contaminant sources, including agricultural runoff, oil/gas wells, inadequate septic systems, leaking underground storage tanks, and road and rail bridge crossings. As a result, the surface water supplied to these plants is considered to have a high susceptibility to contamination. Del-Co also obtains groundwater from its wellfield in Knox County, which is treated by the Thomas E. Steward Plant. In October 2001, the Ohio EPA approved Del-Co’s Wellhead/Drinking Water Source Protection Plan for this wellfield. The source water here is also considered to have a relatively high susceptibility to contamination due to the lack of a significant confining layer above the sand and gravel aquifer, and the presence of numerous potential contamination sources within the protection area. Historically, the DelCo public water system has effectively treated its source waters to meet drinking water quality standards. By implementing measures to protect the Olentangy River, O’Shaughnessy Reservoir, Alum Creek Reservoir, and the local aquifer, the potential for water quality impacts can be further decreased.