Think road salt won't reach your drinking water? Ask Madison
When we toss down the road salt that's ubiquitous with icy, snowy winters in the North, the salt doesn't just disappear after it clears up the roads and sidewalks.
In fact, it's starting to get into drinking water in places across the Midwest and New England — posing an emerging threat to water supplies and a health risk for people on sodium-restricted diets or with high blood pressure.
"The salt doesn't just evaporate, it doesn't break down. Once it's applied in the environment, it's got nowhere to go. It goes into the soil, or it goes into the lakes. It doesn't just disappear," said Joe Grande, the water-quality manager in Madison, Wis.
Madison is one of the more notable cases of drinking water contamination by sodium chloride. Other instances have been reported in places like Baltimore, Washington, D.C., and parts of New Jersey — including one extreme case in the city of Brick, chlorides damaged lead water pipes, causing the toxic metal to leach into drinking water.
Most people start tasting salt in water once it reaches concentrations of 250 milligrams per liter. Even before that point, though, water can start to taste off.
Off-tasting water, and no good way off salt
Faith Fitzpatrick lives in Madison's Spring Harbor neighborhood. Her well has been among the hardest hit by road salt pollution. Some of her neighbors with low-salt diets have installed filtering systems in their homes.
She describes the tap water as having a mineral-laden, carbonate taste. It's not like dipping your cup into the Dead Sea, but it's different.
The water, Fitzpatrick said, "does taste a little saltier, but it's not like you would drink it and say, 'Oh my gosh that's super salty.'"
Private applicators are partly to blame for how the water got this salty in Madison. They'll sometimes put down 10 to 15 times the recommended amount of salt, Grande said, which doesn't help the safety.
So, the city Water Utility is trying to educate applicators on how road salt affects the water and how overuse is wasteful.
"Just because you put down twice as much salt as is required it doesn't necessarily make it twice as safe," Grande said. "We're basically trying to get out the message, 'you're really just throwing this salt away.'"