Arlington County, Virginia: drinking water report. Arlington County sits directly across the Potomac River from Washington, DC, encompassing cities like…
Arlington County sits directly across the Potomac River from Washington, DC, encompassing cities like Arlington, Rosslyn, and Crystal City. The county receives its drinking water primarily from the Potomac River through two regional systems: the Washington Aqueduct (operated by the U.S. Army Corps of Engineers) and the Fairfax Water system. This urban county of roughly 240,000 residents depends entirely on treated surface water, with no private wells in residential use.
Arlington's water quality reflects both the challenges of drawing from a major river system and the strengths of well-maintained treatment infrastructure. The Potomac River collects runoff from a vast watershed spanning multiple states, bringing agricultural chemicals, urban pollutants, and legacy industrial contaminants downstream. The Washington Aqueduct treats this water at facilities in DC before distribution to Arlington, while some southern portions of the county receive water from Fairfax Water's treatment plants.
Lead contamination remains the most pressing concern for Arlington households, though the problem originates in building plumbing rather than source water. Properties constructed before 1986 (which describes much of Arlington's housing stock) often contain lead service lines, lead solder, or brass fixtures that leach lead into drinking water. The county's hard water, while safe to drink, can accelerate corrosion in older pipes. Elevated lead levels typically appear after water sits stagnant in pipes overnight or during work hours, a pattern common in Arlington's many older apartment buildings and townhomes.
Recent EPA monitoring under the UCMR5 program has detected PFAS (per- and polyfluoroalkyl substances) in Potomac River source water, consistent with patterns across the Mid-Atlantic region. These forever chemicals originate from firefighting foam used at Reagan National Airport, military installations, and industrial sites upstream. While treatment plants remove some PFAS, not all variants are effectively filtered by conventional methods. Northern Virginia utilities have generally reported PFAS detection in the low parts-per-trillion range, below EPA's newly proposed limits but still present in finished drinking water. Disinfection byproducts (trihalomethanes and haloacetic acids) form when chlorine reacts with organic matter in the Potomac, occasionally approaching but typically staying below federal limits.
If you live in a building constructed before 1986, flush taps for 30-60 seconds before using water for drinking or cooking, especially first thing in the morning. Consider testing your water for lead if you have young children or are pregnant, since building-specific plumbing creates variation between properties even on the same water system. For PFAS and disinfection byproducts, carbon filtration or reverse osmosis systems provide the most reliable removal. Check your water for current data from your specific address, review our water filter guide for treatment options that match Arlington's contamination patterns, request a detailed report for comprehensive testing results, or visit the Virginia state page for broader context on water quality issues affecting the Commonwealth.