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Arlington health officials are urging residents to avoid recreational activity in the Potomac River as authorities respond to a sewage spill that has released more than 200 million gallons of wastewater.

The county’s drinking water remains safe and continues to undergo regular testing under state and federal standards. Arlington’s water is treated at the Washington Aqueduct’s Dalecarlia Water Treatment Plant, whose primary intake near Great Falls is upstream from the spill and has not been affected.

Arlington Public Health Director Dr. Deidra D. Parrish endorsed the Virginia Department of Health’s recreational water advisory for the river.

Residents should avoid contact with water in the advisory area and follow signs posted at access points. They should also stay away from water with foul odors, discoloration, or dead or dying fish.

Anyone who comes into contact with the water should promptly wash exposed skin with soap and water. Clothing, fishing equipment, life vests, ropes, paddles, and other exposed items should also be rinsed or washed.

Sewer collapse released wastewater

The spill began after part of DC Water’s Potomac Interceptor sewer line collapsed in Montgomery County, Maryland, on Jan. 19, 2026. The failure sent more than 200 million gallons of raw sewage into the river.

DC Water installed a temporary bypass on Jan. 27 to route wastewater around the damaged section and back into the District’s sewer system. That bypass failed earlier in the month after pumps became clogged with wipes marketed as flushable.

An upgraded bypass was expected to be completed within days. DC Water estimated that emergency repairs to the collapsed interceptor would take four to six weeks.

Monitoring at several locations along the Potomac has shown bacteria levels declining over time and farther from the drainage channel. Officials nevertheless advise residents to remain cautious and follow recreational warnings throughout the river corridor.

Arlington streams show no spill impact so far

The discharge is not expected to harm water quality in Arlington’s streams. However, the county’s bacteria-monitoring program is collecting additional samples from Four Mile Run to check for possible local effects.

Testing so far has found low E. coli levels and no evidence that the sewage spill has affected Arlington streams.

Arlington generally advises people and pets to avoid swimming or full-body submersion in local streams because E. coli can enter the water from urban wildlife, pet waste, and other sources. County monitoring indicates bacteria levels are usually suitable for wading and fishing but tend to rise from May through October and during the 48 hours after a major rainstorm.