About Your Water Quality

Del-Co operates four water treatment plants having a combined capacity of 33 million gallons per day. The water source for three of the plants is from surface waters such as a river and reservoir, the fourth plant obtains its water from wells.
Del-Co uses the same treatment techniques at all its plants so that the water quality is the same for all of our customers.

In a nutshell . . . raw water from the source first flows to single-stage solids contact basins that combine clarification and softening into a single unit. Raw water hardness varies from about 180 mg/l in surface waters to 350 mg/l in ground waters. Using lime, water is softened to 105 mg/l. Next, carbon dioxide is added to lower the pH thereby ending the softening reaction and stabilizing the water. Water then passes through rapid sand filters to further remove small particulate matter. Finally, chlorine is added for disinfection prior to sending it to the distribution system.

Olentangy Water Treatment Plant
Constructed in 1973, this is the original Del-Co water treatment plant. With a capacity of 7.1 million gallons per day, it serves the southwestern and south central parts of Delaware County. The raw water source for this plant is the Olentangy River. This site is also home to the De-Co Water administrative offices.


Ralph E. Scott Water Treatment Plant
Named after one of the founders and first board president, this plant has a capacity of 6 million gallons per day and is located below the dam embankment to the Alum Creek Reservoir, which serves as the water source for the plant. This plant serves the south central and eastern side of Delaware County.


Thomas E. Steward Water Treatment Plant
Named after a former board member and general manager, this plant is located in western Knox County. The TES plant is the only ground water plant on the Del-Co system and has a capacity of 4 million gallons per day. This plant serves customers in Morrow and Marion Counties, and a portion of north central and northeastern Delaware County.


Timothy F. McNamara Water Treatment Plant
Named after one of the founders and former board member, this plant was constructed to meet the high summer peak demands in southern Delaware County. Its all-steel above-ground construction made it a cost-effective construction project, and limits it use to summer months. The raw water source for this plant is Alum Creek, just below the Alum Creek Reservoir. It has a capacity of 4 million gallons per day.


Typical raw water pump station intake
This one, located on Alum Creek below the Alum Creek reservoir pumps water to the Timothy F. McNamara treatment plant.