WSSC Lists $155 Million in Electrical Fixes for the Potomac Plant That Lost Power Sept. 29

WSSC Water estimates it needs $155 million in electrical upgrades at its Potomac Water Filtration Plant, the plant that lost power on September 29 and left the utility asking all 1.9 million of its customers to use water only for essential purposes. Three projects account for $130 million of that, according to the general manager’s report prepared for the WSSC Commission’s October 21 meeting.

The same report shows $4.5 million in electrical work at the plant this fiscal year and $6 million next year.

WSSC is also asking every household to be ready for another outage. At an October 15 event with state and county emergency officials, it urged customers to “store at least one gallon of water per person per day for a minimum of three days,” or at least three gallons for each person in the home.

FOX 5 reported on September 30 that a WSSC assessment had found 10 electrical projects at the plant costing about $150 million over 10 years. WJLA reported on October 15 that $130 million of it was for the top three and that WSSC was seeking federal or state money rather than passing the cost on to customers. WSSC’s own report puts the total at $155 million. The three largest projects, as WSSC names them, are $48 million for “High Voltage Switchyard Improvements,” $49 million for “Outdoor Substation 3 High Zone and Solids Improvements” and $33 million for “Outdoor Substation 2 and Raw Water Pumping Station Improvements.” The slide labels them a “Request of an Estimated Total of $130M” but does not say to whom the request is addressed.

What happened on September 29

The Potomac plant, on River Road in Potomac, is the larger of WSSC’s two filtration plants and serves about 70% to 75% of its customers, according to WSSC. It runs on two electrical feeds from Pepco. In mid-September, one of them was taken out for maintenance, according to WSSC’s account. The other “failed at approximately 4:30 a.m.” on September 29 and could not be restored.

WSSC issued its essential-use-only request at 8:45 a.m. Its other plant, on the Patuxent River, was producing 90 to 95 million gallons a day, “which is not enough to meet demand,” the utility said. Pepco restored the feed that had been down for maintenance at about noon, but problems inside the plant kept it from restarting until about 3:45 p.m. That evening, as storage refilled, it was about 89 million gallons, and WSSC’s production director said he would feel more comfortable at 105 million gallons, WTOP reported. A WSSC spokesperson later told WJLA that crews found a workaround just in time, with some areas only hours from running dry. WSSC has said that drinking water remained safe and service was maintained throughout the event, in its October 15 statement.

WSSC lifted the request at 5 p.m. on September 30 and said power inside the plant was fully restored on October 7. On the night of the outage, WSSC said “the failed component on the second feeder has been identified and replaced.” After power was restored to the plant that afternoon, Pepco told Bethesda Today that power was available to the facilities and that its initial findings showed the issue was due to WSSC equipment. At the time, WSSC said an unknown electrical problem at the plant was keeping it from bringing systems back online. We did not find a public root-cause report in WSSC’s releases or Commission materials.

It has happened before. After the June 2012 derecho, a Montgomery County Council staff memo quoted the county’s after-action review: “For the second time in 2 years the WSSC Potomac water treatment facility had both of its electrical feeder lines damaged and out of service.” The review recommended discussing with WSSC “the purchase and installation of back-up power generators for its Potomac treatment facility.” Those outages were caused by storm damage. This time, one feed was out for planned maintenance when the other failed.

Why there is no backup generator

The plant still has no generator that can run it. On the day of the outage, a WSSC spokesperson told WJLA that there is no generator on site capable of providing the power needed to run the plant.

The October report explains why. Five diesel generators, plus a sixth as a backup, would produce 50 million gallons of water a day, “equivalent to one-third of typical production,” according to the report. They would need a building 250 by 130 feet and take 75 to 77 weeks to arrive, and “the only viable site for the fuel tanks is upstream of the water intake and adjacent to the river; storing a large volume of diesel in this area poses a significant risk to the source water.”

WSSC is planning a natural gas and solar microgrid for the plant instead, designed to cover about 65% of the plant’s power needs. The report lists it as in the planning phase. It grew out of a feasibility study funded by a $100,000 state Resilient Maryland grant awarded in fiscal 2022.

Who pays

The electrical work comes as WSSC sets next year’s rates, though neither rate document ties a specific increase to the Potomac plant. WSSC’s rates rose 5.0% this fiscal year, according to County Council staff. For next year, WSSC’s base case is a 7.0% increase, which Council staff support. A WSSC cost-of-service study, in a draft marked for deliberative purposes, recommended 11.7%. Each 1% raises about $11 million and adds about $3.10 a quarter to an average residential bill, according to Council staff.

“We cannot continue to place the burden of needed investments solely on the backs of our customers,” WSSC General Manager Kishia Powell said in an October 15 statement. At a County Council committee hearing on October 12, Council President Natali Fani-González said, “I don’t think we get to say ‘no’ when it comes to basic infrastructure investment that we need,” FOX 5 reported. Powell told the committee that “we believe they’ve identified the specific issues, but overall the power system at Potomac is aged just as the plant is. We’re dealing with original equipment,” FOX 5 reported.

We covered the September 29 request as it happened.

Still unanswered

• Which areas came closest to running out of water, and how low storage fell there.
• What failed, on the feeder and inside the plant, and whether WSSC will publish a root-cause report.
• The assessment behind the $155 million: who wrote it, when, and whether it will be released.
• Who the $130 million request is going to, and how it squares with the $11.8 million in Potomac electrical work FOX 5 reported WSSC described to the Council.

We have not yet put these questions to WSSC; this story will be updated with any response.

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