Chloride Pollution

Chloride is now one of the priority pollutants affecting our freshwater resources. It takes just one teaspoon of salt to permanently pollute five gallons of water, or one bag of sidewalk salt can pollute over 10,000 gallons of fresh water. We all have to do our part to prevent chloride pollution! The Minnesota Chloride Management Plan (PDF) asks everyone to use less salt!

Sources of Chloride Pollution

The primary sources of chloride pollution in Red Wing are deicing salt and water softeners. Salt is applied to our roads and sidewalks to melt ice and keep our paved surfaces safe for travel. Salt is also used in water softeners to recharge the resins. Once the salt is used, it is sent to the sanitary sewer, where is passes through the wastewater plant untreated and into our freshwater bodies. Chloride is very difficult to remove from water using traditional water and wastewater treatment methods. Once it is in our fresh water, there is no feasible way to remove it.

Health and the Environment

Fish and aquatic bugs need fresh unsalted water to be able to thrive. Chloride is toxic to fish, aquatic bugs, and amphibians, as well as other plants and animals. Take a look at the areas around your sidewalk in the spring. Have you noticed dead or yellow spots of grass? This could be from the effects of deicing salt used the previous winter. Learn more about the effects of deicing salts on landscapes from the University of Minnesota Extension. Maybe you use “pet-safe” deicers because we know deicer salt is bad for our pets. WI Salt Wise covers safe sidewalks for pets in this video

Chloride has also been found making its way into our drinking water resources. Most Minnesotans, including us in Red Wing, obtain our drinking water from groundwater aquifers. These aquifers are now showing elevated levels of chloride, especially around urban areas. This is due to chloride polluted groundwater soaking into the ground and recharging the aquifer.

Chloride and salt is also hard on our infrastructure and equipment. It corrodes concrete and road surfaces, and almost anything made of metal. Think of your car after a long salty winter. If you don’t wash off that white crust, you will likely have rust spots to deal with later.

The Dilemma

Many lakes and water bodies have already been declared “impaired” for chlorides. This means that they cannot meet their designated use, such as aquatic life. The location of these chloride-polluted water bodies directly correlates to road density, meaning more roads equals more salt. As areas become more urban, there are more roads and paved surfaces and more salt used in the winter months (as well as more people with water softeners). Most people have come to expect a very high level of service from winter maintenance professionals, or plow drivers, to remove snow and ice as quickly and completely as possible so we can get where we want to go. This increased pressure often leads to more salt use on roads, parking lots, and walkways. Nobody wants to get hurt in an accident due to ice, and nobody wants the liability of someone getting hurt on their icy surface. This is the dilemma Minnesota faces.

What Is Red Wing Doing?

Winter maintenance professionals, our plow drivers, at the City of Red Wing attend a Smart Salting training, which helps operators improve their decision making in salting and make the deicer application more effective. This helps us use less salt while keeping roadways safe. We also hold an annual snow meeting with plow drivers to discuss the best practices and the “Snow & Ice Control Policy”. This policy details how, when, and where to use deicers. See more here.

The City uses alternatives to traditional road salt such as prewetting/pretreating or brining the roads with Ice Bite 55, a substance derived from sugar beets. This helps prevent the ice from forming on the roadway, so it is more completely removed by plowing and less road salt is required. You may have noticed this application on hilly areas here in town. It looks like many parallel lines, or wet tracks on the road shortly before a snow storm. This helps us to use 1/3 less salt during a winter event.

The City also regulates how and where bulk deicers can be stored in Red Wing. This is located in the zoning code. Any deicer over five tons in solid form or 1,000 gallons in liquid form must be stored under cover and on an impervious surface. It also cannot be located near a wetland, water body or a drainage area where snow melt and runoff could carry deicer to the water.

What Can You Do?


Make sure your water softener is set properly. Check out the tools here through the Madison Metropolitan Sewerage District.

Use sidewalk deicers sparingly, and under the right conditions. Check out this Salt Tipcard (PDF) from Clean Water Minnesota. 

Choose a different deicer. Learn how in this Choosing a Deicer brochure (PDF) from Nine Mile Creek Watershed District. 


Take a free Smart Salting Class for Property Management.

Check out these videos on winter maintenance training for small sites

Additional Resources