The U.S. Army Corps of Engineers Baltimore District is re-procuring an indefinite-delivery indefinite-quantity single-award contract for aluminum sulfate and polyaluminum chloride. These chemicals support water treatment operations at the Dalecarlia and McMillan Water Treatment Plants in Washington, D.C. The Washington Aqueduct supplies potable water to approximately one million people in the District of Columbia and Northern Virginia. No specific budget amounts or non-bid timelines are mentioned in the description. Performance of services will occur at the Washington Aqueduct Division in Washington, D.C.