Army engineers to explore secondary water supply source for DC

Study funded to look for alternative drinking water source in DC

Here’s something you may not know; 78% of the D.C. area is reliant on the Potomac River for drinking water. In D.C. and Arlington County, the river is the lone water supply source. FOX 5's David Kaplan has the story.

WASHINGTON - Here’s something you may not know; 78% of the D.C. area is reliant on the Potomac River for drinking water.

In D.C. and Arlington County, the river is the lone water supply source.

For years, DMV leaders have tried to change that. They're now starting to gain some momentum.

Officials told FOX 5, that D.C. is one of the largest metropolitan areas in the U.S. with a lone drinking water source and, at any given time, around just one day's worth of supply stored up.

If something were to happen to the river, whether it’s a drought or an accidental or intentional spill, it could wreak havoc in our area.

There have been a few close calls before. An oil spill in the early 90s and a few droughts, but for years, D.C., Maryland, and Virginia leaders have collectively tried to come up with a second source of drinking water for this area.

In a bill signed last week by President Biden, a half million dollars was set aside for the U.S. Army Corps of Engineers to look into the best way to do that and how much it would cost.

Mike Nardolilli is the executive director of the Interstate Commission on the Potomac River Basin.

He says there are redundancies built into the current system we have, but an additional supply is important, especially given what their models show about the impact of climate change down the road.

"We think we can handle a run-of-the-mill drought with the resources we have," Nardolilli said. "Our models also show that variability is going to increase. Wet years will be wetter, and dry years will be drier."

Hot, dry summer impacting DC drinking water

FOX 5 is staying ahead of drought conditions in our area. We know officials are closely monitoring the river levels and flow of the Potomac River. While they stress we’re nowhere close to voluntary or mandatory restrictions, they’re still keeping a close eye on it.

In terms of comparable undertakings, four years ago, Atlanta finished a $320 million reservoir build that increased their reserve water supply from about three days to 90 days.

It's hard to say how much a D.C. project would cost, but this is part of the reason they’re formally starting this study.

Nardolilli mentioned a few possibilities being considered, including filling up a barren rock quarry in the area, injecting water into an aquifer, constructing a pipeline from Harpers Ferry, and filtering out the salt in some brackish parts of the Potomac.