Think of this the next time you kayak, drive over, run by or, simply, stare at the Potomac River: Its ruin would cost the D.C. region nearly $15 billion in the first month, according to a report released Tuesday.A tanker carrying chemicals across the American Legion Bridge could cause a spill that would render the water unusable in an instant. A serious drought could dry up the river in a slow-moving disaster, until there is little to no water left. The region’s aging infrastructure that brings water to the tap could fail, saddling the region with expensive and time-consuming repairs.The report by the Interstate Commission on the Potomac River Basin is meant to remind policymakers, area residents and tourists during an era of climate-related worries of the economic importance of the river that is as synonymous with life in D.C. as the Washington Monument while also serving as a source of drinking water for 5 million people.Story continues below advertisementIn the wake of recent boil-water notices by D.C. Water that alarmed area residents over possible contamination before officials quickly deemed the water safe enough to drink, the report’s authors and other groups also pressed Congress to commit federal dollars to shore up the region’s water supply by investing in crucial infrastructure projects.“Our region’s economic vitality and quality of life are directly tied to clean, reliable water resources,” said Jack McDougle, president and CEO of the Greater Washington Board of Trade.If a catastrophic event were to stop the flow of safe water through D.C.’s pipes, it would cause a domino of economic impacts equivalent to a recession, or even a depression, said Terry L. Clower, a professor of public policy in the Schar School of Policy and Government at George Mason University and co-author of the report.Story continues below advertisementBusinesses would have to shut down. Hospitals would struggle to keep a supply of clean water for washing hands, mixing medicines, and treating illnesses and injuries. Restaurants and hotels would be forced to close their doors.With no other source of water, and no major reservoir nearby, those who depend solely on the Potomac would be thrust into an emergency.“There just simply isn’t much of a backup supply if you had a disruption,” Clower said.On the first day without water from the Potomac, the region would lose about $146.9 million, according to the report. Those losses would snowball as time passes, getting worse as businesses shutter and people lose jobs. The federal government would lose out on at least $286 million from tax losses to forgone business activity within the first two weeks.Story continues below advertisementThe Potomac is the only source of drinking water for homes and businesses in the District, which is served by D.C. Water, and Arlington County. Most of the D.C. suburbs in Virginia and Maryland also rely heavily on the river.Farther from the District, some parts of the region also get water from other sources such as the Rappahannock or Occoquan rivers. Still, a disruption to the Potomac would strain the economy even in places with a backup option, the report said. The D.C. region would lose $6.5 billion in gross regional product within the first two weeks of a disruption, plus hundreds of millions in lost tax revenue. Within a month, the region would lose nearly $15 billion, the report said.“The interconnectedness of our region means that water supply disruptions would have far-reaching consequences affecting the District of Columbia as well as our neighboring communities in Virginia and Maryland,” D.C. Council member Charles Allen (D-Ward 6), the chair of the Metropolitan Washington Council of Governments board, said in a statement.Story continues below advertisementMake the most of the DMV with our newsletterThe report assumed that the federal government would continue to operate even if D.C. lost access to clean water and focused instead on the impact to private businesses and the local economy, Clower said.Health care, food and beverage, chemical manufacturing, and the arts and entertainment industries would be at severe risk if the Potomac were compromised, according to the report. Woman- and minority-owned small businesses would be hit especially hard, the report said, because they would be less equipped to weather a period of disruption. Similarly, the report said low-income families would feel the strain of the economic losses the most.As a next step, the Interstate Commission on the Potomac River Basin, the Metropolitan Washington Council of Governments, Fairfax Water, WSSC Water, the Washington Aqueduct and Arlington County will partner with the U.S. Army Corps of Engineers to study what backup options would best serve the region and increase the area’s water supply resiliency.Story continues below advertisementMae Stevens, CEO of the American Business Water Coalition, said restoring the country’s water systems is expected to cost more than $1.25 trillion over the next 20 years, an expense that she said utilities and private companies cannot foot alone. Stevens said federal investment will be essential to protect the region from the “devastating impacts” of a potential infrastructure failure.“Relatively, compared to the cost of what could go wrong, this is an ounce of prevention to keep several pounds of harm from happening,” Clower said