An arm of American Water Works that provides tap water in a few parts of Virginia. They have a system in Hopewell that supplies water they filter themselves; they have two systems in Northern Virginia (Dale City and Alexandria) that were inherited from the old Alexandria Water Company, and resell water produced (partially) by plants in Lorton that were long ago purchased from AWC by Fairfax County.
If you live in Alexandria, the old AWC plant is on Duke Street, near the Washington Masonic Memorial. The two old reservoirs are covered up.