WSSC Water's Potomac Water Filtration Plant made solid overnight progress, but the utility's essential-water-use-only request remains in effect for all 1.9 million customers in Montgomery and Prince George's counties.

WSSC Water said in a 6 a.m. Wednesday, Sept. 30, update that the plant at 12200 River Road increased production overnight and refilled storage across the distribution system. Water storage is returning to normal levels and power delivery is adequate, the utility said, but the situation remains critical.

The plant is running on a temporary electrical configuration. Crews are working to restore permanent power and full normal operations.

There is no boil water advisory. WSSC Water says its drinking water remains safe.

The utility said it will monitor production, demand and the status of permanent electrical repairs and decide later Wednesday whether to lift the conservation request.

In a 10:45 a.m. update posted on X, WSSC Water said the situation had stabilized but critical electrical work continues. Montgomery County Executive Marc Elrich was scheduled to provide a public update at 12:30 p.m. Wednesday, WJLA reported. The outcome of that briefing was not available at publication.

How the outage unfolded

The plant has two electrical feeds and can run on either one. One feed had been taken offline in mid-September for routine Pepco maintenance. The second feed was carrying the full load. It failed at about 4:30 a.m. Tuesday, Sept. 29, knocking out water production.

WSSC Water issued the essential-use request at 8:45 a.m. Tuesday. The Potomac plant normally produces 100 to 120 million gallons of drinking water per day and serves about three-quarters of WSSC's customers. The utility's other plant, Patuxent, was producing 90 to 95 million gallons daily, well short of the system's average 170-million-gallon demand.

Pepco restored the first feed around noon Tuesday. But internal electrical problems inside the plant delayed the restart. As Bethesda Magazine reported Tuesday, WSSC described "an unknown electrical problem at the plant" that was preventing systems from coming back online. Pepco told the magazine that power was available and initial findings pointed to WSSC equipment.

Plant crews resolved the internal fault and restored water production at about 3:45 p.m. Tuesday. By 9:35 p.m., WSSC Water said both feeders had commercial power, a temporary internal workaround was in place, and the plant was operating at full production. The failed component on the second feeder was identified and replaced.

WSSC Water GM and CEO Kishia L. Powell addressed the public Wednesday in a video posted to the utility's X account, calling for continued investment in water infrastructure.

What residents should do

Until WSSC lifts the request, the utility asks customers to use water only as necessary, avoid all outdoor water use including lawn irrigation, and limit use of washing machines, dishwashers and toilet flushing.

Residents can report water emergencies to WSSC at 301-206-4002.