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Drinking Water

Water quality     Water supply     Water treatment     Fluoridation     Water distribution 

Water Quality

We are committed to providing high quality drinking water to our customers. OWASA is a member of the Partnership for Safe Water, a water industry association which promotes excellence in drinking water treatment.

In May 2011, OWASA became the ninth water utility in the United States to receive the Partnership's "Excellence in Water Treatment" award. Please click here for more information. For details about our drinking water quality, please use the following links:

If you have any questions or comments about our drinking water or would like your OWASA drinking water tested, please contact our Drinking Water Laboratory at 919-537-4228 or

On November 19, 2013, a contractor hired by OWASA  began a project to clean, paint and do structural work on our water tank west of Piney Mountain Road in Chapel Hill. We estimate this work may be complete in April. For more information, please click here.

Water Supply

OWASA's water supply originates as rain in the Cane Creek and University Lake watersheds. A watershed is an area where all the water that is under it or drains off of it goes into the same place. As can be seen in this watershed map, about 90 percent of our watersheds are in Orange County. The remaining 10 percent of our watersheds are in Alamance and Chatham Counties.

Within these watersheds, water is stored in three reservoirs:

  • The Cane Creek Reservoir, which is about 9 miles west of Carrboro, can store about 3 billion gallons from its 32-square mile watershed and has a surface area of about 540 acres. More than 3,000 acres of watershed land is either owned by OWASA or protected through conservation easements.
  • University Lake, which is just west of Carrboro, can store about 450 million gallons from its 30-square mile watershed and has a surface area of about 200 acres.
  • The Quarry Reservoir, which is in the University Lake watershed about 3 miles west of Carrboro and can store about 200 million gallons.
  • OWASA also has an allocation of 5 percent of Jordan Lake’s water supply storage capacity, which can yield about 5-6 million gallons per day (MGD). Jordan Lake will become increasingly important to OWASA in the event of severe drought or other emergency – especially in the 20+ years until the expanded Quarry Reservoir is on line. Retaining that allocation and gaining access to Jordan Lake is essential to meeting our customers' needs today and in the future.

The Cane Creek/University Lake/Quarry Reservoir system can support an average yield of about 10.5 million gallons per day (MDG) during severe drought conditions (current demand is about 7 MGD). For additional information about our water supply, including our future plans, please see our Long-Range Water Supply Plan.

Water Treatment

Jones Ferry Road Water Treatment Plant

While water in OWASA's reservoirs is very clean, it requires treatment before it is drinking water quality. Water is pumped from the reservoirs to the Jones Ferry Road Water Treatment Plant in Carrboro, where impurities are removed through chemical and physical processes. The Jones Ferry Road Water Treatment Plant can treat up to 20 MGD.

When water from the reservoirs enters the treatment plant, chemicals are added to make the very small particles that are suspended in the water clump together so they can be removed in tanks designed to separate the solid particles from the water. After most of the solid particles have been removed, a small amount of chlorine (bleach) is added for initial disinfection and the water is further cleaned by filtering it through layers of anthracite coal and sand. We then add fluoride for dental health and make sure the pH of the filtered water is at the proper level. The water then flows to a large tank where ammonia is added to the water and combines with chlorine to form "chloramines" to further disinfect the water. The treated water now meets all drinking water standards and is ready for use by our customers. The solids that have been removed from the water during treatment are taken to a private company for composting.

Fluoridation of drinking water

In accord with recommendations of the American Dental Association, US Centers for Disease Control and Prevention and other public health-related organizations, OWASA adds fluoride to drinking water to help prevent tooth decay. The  level of fluoride in our water is about 0.7 of one part per million. (One part per million is like a penny is $10,000.)

For more information, please click here for our webpage on fluoridation.

Water Distribution

The drinking water is pumped from the Jones Ferry Road Water Treatment Plant to water storage tanks and through a system of about 380 miles of pipes that are designed and operated to deliver an adequate volume of water at sufficient pressures to meet the demands of our customers including adequate flow for fire protection.

Drinking Water System