The Source of Arlington’s Water

Potomac River Arlington’s water comes from the Potomac River. It is treated at the Dalecarlia Water Treatment Plant run by the Washington Aqueduct, a division of the Baltimore District, U.S. Army Corps of Engineers.

Treated water is pumped from the Dalecarlia plant in the District of Columbia to Arlington County, where it’s conveyed via a network of approximately 500 miles of pipeline to homes and businesses. In addition to the pipelines, the water distribution system includes approximately:

  • 16,000 valves
  • 3,700 fire hydrants
  • 37,200 water service connections

Typical daily water consumption for our customers is approximately 23 million gallons a day (MGD), with a peak approaching 35 MGD on the hottest summer days. Drinking tap water is safe and much less expensive than bottled water.

Willston Water Distribution System

The Willston Water Distribution System serves approximately 2,000 citizens (or 1% of residents) and is located on the western edge of the County. While the rest of the County receives its water directly from the Dalecarlia Water Treatment Plant in the District, Arlington purchases water for the Willston area from Fairfax Water. Fairfax Water receives its water from the Dalecarlia and McMillan Water Treatment Plants, which are also run by the Washington Aqueduct.


Arlington’s water distribution system is operated from the Water Control Center 24 hours a day, 365 days a year. Operators control the many pumps and valves that allow the system to deliver water to your home. Among the facilities that are operated and monitored by our staff are three water storage facilities comprising 32 million gallons, five pumping stations and 12 pressure monitoring sites dispersed throughout the County.


You Want Water, We Got Water: The County used approximately 7.7 billion gallons of water in Fiscal Year 2022. Drink up!