WSSC has Resolved Water System Issue

From a WSSC press release: September 29, 2026, at 9:35 p.m. :

• Potomac Water Filtration Plant Operating at Full Production as Storage Levels Recover
• No Indication the Outage Was Caused by a Cyberattack or Bad Actor
• No Boil Water Advisory Is in Effect; Water Remains Safe to Drink and Use

The electrical issue at WSSC Water’s Potomac Water Filtration Plant has been resolved, and the plant is operating at full production. Water storage levels and distribution-system conditions are steadily recovering and are expected to return to their usual range soon. Until that recovery is complete, WSSC Water continues to ask its 1.9 million customers in Montgomery and Prince George’s counties to limit nonessential water use through the following measures:

• Use water only as needed.
• Postpone outdoor water use, including lawn irrigation.
• Limit toilet flushing where practical.
• Delay use of washing machines and dishwashers when possible.

 Current Status

• Drinking water remains safe to drink and use, and no boil water advisory is in effect.
• Commercial power is available to the plant, the internal electrical problem has been corrected, and the facility is operating stably at full production.
• System storage declined during the outage but is now replenishing. Levels are expected to continue improving overnight and into tomorrow, when demand is lowest.
• WSSC Water electrical teams remain on site to monitor operations and confirm that the system continues to perform as expected.
• The failed component on the second feeder has been identified and replaced. WSSC Water is coordinating with Pepco on returning that feeder to service after the system has fully stabilized.
• WSSC Water expects to reevaluate conditions in the morning and lift the essential-water-use-only request once storage and pressure have returned to normal operating levels.

 Background

The Potomac Water Filtration Plant has two electrical feeds and can normally operate fully on either one. One feed had been taken out of service in mid-September for planned Pepco maintenance intended to improve the reliability and resilience of power supplied to the plant.

While that reliability work was underway, the second feed—the plant’s sole active power source at the time—failed at approximately 4:30 a.m Tuesday. Although the planned maintenance was meant to strengthen the system, taking one feed offline left the plant without its usual redundancy when the remaining feed failed. Pepco immediately mobilized and restored the feed that had been under maintenance at approximately 12 p.m.

An internal electrical issue then delayed the plant’s restart. Crews identified and corrected the problem, returning the facility to full production at approximately 3:45 p.m. WSSC Water is reviewing the incident, including the loss of redundancy during planned maintenance, to determine what additional safeguards are needed.

Temporary conservation remains important while storage levels recover, but normal water-use conditions are expected to resume soon. WSSC Water will provide a final update when the essential-water-use-only request is lifted. Customers can check the WSSC Water website and social media, X (@WSSCWaterNews) and Facebook for the latest information.