Chloride

Curbing salt use to protect our freshwater resources

In Wisconsin, we rely on salt to keep our roads, driveways and sidewalks safe in the winter and to soften the water in our homes on a daily basis. But our heavy salt use comes with a cost: excess chloride in our waters.

The District’s Nine Springs Wastewater Treatment Plant receives 220,000 pounds of salt per day; this is equal to three semi-trailers or 5,500 40-pound bags of water softener salt daily! Unfortunately, the treatment plant isn’t designed to remove dissolved salt from water. So chloride, a component of salt, passes through the treatment plant into the freshwater streams we discharge to.

In addition to water softener salt, overuse of road and sidewalk salt can ultimately infiltrate into our lakes, streams and groundwater and make them salty. At high enough levels, excess chloride from salt can threaten freshwater plants and animals, which can’t tolerate salt water.

One teaspoon of salt can permanently pollute 5 gallons of water. Once chloride is in the water, there is no easy way to remove it.

We all play a role in salt reduction

While it’s easy to add salt to water, it’s costly and energy-intensive to remove it. In 2015, the District completed a chloride compliance study that looked at sources and potential treatment options. At that time, the study showed it would cost over $400 million to add chloride-reduction technology to the treatment plant, which would result in higher sewer bills for all users.

Fortunately, there is another way. Rather than adding costly treatment to protect our freshwater, we can more cost-effectively reduce salt use at the source. Through the collective actions of residents, businesses, salt professionals and others, we help reduce the amount of salt that ends up in our water.

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