What We Do


The Washington Aqueduct, managed by the U.S. Army Corps of Engineers, provides wholesale water treatment services to DC Water and its partners in Northern Virginia, Arlington County and Falls Church. DC Water purchases approximately 75 percent of the water produced by the Aqueduct's two treatment facilities, the Dalecarlia and McMillan treatment plants, and thus is responsible for 75 percent of the Aqueduct's operating and capital costs. Under federal legislation and a memorandum of understanding enacted in 1997, DC Water and its Northern Virginia partners have a much greater role in oversight of the Aqueduct's operations and its capital improvement program.

Major projects underway in this year's plan include:

McMillan Water Treatment Plant Improvements
This includes a variety of projects at the McMillan plant, which is adjacent to DC Water's Bryant St. pumping station, including elevator and crane replacements and building renovations.
Transmission & Storage Facility Improvements
This includes a variety of projects including
  • renovation of the booster pumping station,
  • replacement of sluice gates,
  • improvements to the Georgetown Reservoir,
  • transmission main rehabilitation,
  • and improvements to the Little Falls pumping station.
Dalecarlia Water Treatment Plant Improvements
This includes a variety of projects at the Dalecarlia plan, including building, roadway and security improvements and clearwell cleaning and disinfection.

Near-term projects include Georgetown Reservoir improvements, including rehabilitation of the dividing wall and sluice gates, and renovation of the laboratory and chemical buildings which will renovate the four existing, 40-year old labs.

In addition to these projects, the Aqueduct has identified a project that could occur depending on the outcome of permit negotiations and other regulatory changes that are being considered by the EPA. Currently, solids that settle out from water in the Dalecarlia and Georgetown Reservoirs are periodically discharged into the Potomac River during high river flow conditions. The draft NPDES permit received by the Aqueduct requires development of a plan to remove 85 percent of incoming sediments and not return them to the Potomac River. The Aqueduct, DC Water and the other wholesale customers are working with the EPA to better understand this requirement and to identify the technological alternatives available to meet this requirement. The Aqueduct has tentatively identified projects to address this requirement.


What We Do