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Rainfall May Improve Drinking Water Issue

Water faucet
Flickr: Luis

Columbus city officials say it’s difficult to know how long the drinking water advisory will last. The current estimate is a couple of weeks.

Rainfall during the next few days has the potential to help reduce the level of nitrates in the Dublin Road drinking water treatment plan. But City of Columbus Water Division administrator Rick Westerfield said it depends on where it rains.

“If it [rains] in certain portions of our watershed, say further north of O’Shaughnessy Reservoir, the rainfall could provide additional dilution of the nitrates," Westerfield said. "Or if the rainfall hits certain areas it may wash more pollutants off into the river.”

Westerfield added even though an advisory has been issued, the nitrate levels in the water are relatively low.

“It’s not like we’re hundreds of milligrams per liter above the limit," Westerfield said.

The EPA requires an advisory if nitrates reach 10 milligrams per liter in drinking water. What does that mean? The City of Columbus provided the following example: "If a bucket of water has nitrate in it at a level of 10 parts per million (or mg/L), and the bucket of water had 1 million drops of water in it, 10 of those drops would be nitrate."

“We still have to issue the advisory because the advisory is a U.S. [Environmental Protection Agency] drinking water requirement, and it is very conservative on protection of public health," he said. "But you’ve got to keep in mind that we’re very close to the limit, even under the current situation.”

The level of nitrates at the Dublin treatment plant dropped slightly in the past day to 11.4 milligrams per liter. 

Westerfield said during a “normal” summer, local drinking water can have 3 milligrams of nitrate per liter after rainfall. 

Health officials say infants younger than six months and pregnant women should not drink or cook with tap water until the advisory is lifted.