Rivanna Water & Sewer Authority (RWSA) operates five drinking water treatment plants with a combined nominal capacity of 23.0 million gallons per day (MGD). The effective maximum day operating capacity, taking into account operating goals and system constraints, is 18.7 MGD. The safe yield of our water supply is currently estimated at 12.3 MGD. Treated water then flows to the City of Charlottesville and/or the Albemarle County Service Authority's municipal water distribution systems through RWSA's water transmission system of pipes and pump stations fed from our water treatment plants. Highly skilled, trained and licensed staff operates and maintains the drinking water treatment processes and regulatory compliance within strict Federal/State water production permits.

RWSA is recognized as a leader in the production of reliable, pure, safe drinking water, with an impressive record of facility permit compliance. RWSA must comply with Virginia Department of Health (VDH) permit limitations, who enforces the Federal Safe Drinking Water Act for the U.S. Environmental Protection Agency. The Virginia Department of Health conducts frequent facility inspections and requires monthly submittal of operational reports.

Supporting Our Community Needs

Our reputation is for not only meeting but exceeding requirements in our production of pure drinking water, and we have initiated the costly improvements needed to meet safety regulations, and ensure responsive, reliable service to our customers. We also provide an ecological balance between the water needs of humans and fish by overseeing an in-stream flow monitoring program that releases water past the dams from our water supply reservoirs on the South Fork Rivanna and Moormans Rivers. The enhancement of this program, developed in a partnership with The Nature Conservancy, was recognized in a national journal publication in 2007.

RWSA is a strong advocate for the responsible use of water and encourages innovative water conservation practices and public education. As a wholesale agency, we work in partnership with the Albemarle County Services Authority and the City of Charlottesville, who as the two retail agencies in our community are responsible for setting public policies pertaining to water conservation and use.

RWSA also operates a hydroelectric plant at the South Fork Rivanna Dam, which can generate up to 1 megawatt of power, to help offset the power requirements for the water treatment and pumping processes. In a partnership with StreamWatch, we have developed procedures for optimizing power generation while also protecting the quality of the South Fork Rivanna River below the dam.

The Water Treatment Process:

Treating water protects human health. Without adequate water treatment, there would be waterborne pathogens potentially causing life-threatening disease in our local population.

When untreated water enters our drinking water treatment plants, it is referred to as raw water.

Water treatment is highly complex, involving physical, chemical processes.

There are Several Steps to Water Treatment:

Preliminary Treatment (Screening & Presedimentation): Removes grit (sand), debris, and material that can clog or damage plant equipment.

Coagulation/flocculation: Is a chemical treatment process designed to convert small, lightweight, nonsettleable particles into larger, heavier particles that will settle. Coagulation/flocculation must occur before sedimentation in order to improve the performance of that process.

Sedimentation: Settles out many of the suspended particles in the water, thus reducing the load on the filters. In the sedimentation process, the flow rate is slowed as the water passes through a tank (called a sedimentation basin or clarifier), which allows the particles to settle by gravity.

Filtration: The major purpose of filtration is to remove suspended material from the water. This suspended material can include remaining particles from coagulation/flocculation and the sedimentation processes. These suspended particles are removed when the water passes through a bed of granular material known as filter media. The filter media is usually sand or some combination of sand, anthracite coal, garnet, or similar substances.

Disinfection: Kills disease-causing organisms. Chlorination is performed as the final treatment process and is the most common means of disinfecting drinking water. All drinking water must receive some type of disinfection to help ensure that disease causing organisms are not present.