Lake Calhoun (photo by Jim Herzog)

We have long known that salt applied to roads, parking lots and sidewalks to reduce slip and fall hazards are harmful to our landscapes and water quality. The MPCA’s draft 2014 list of impaired waters adds many popular metro-area lakes and rivers to the list because of excess chloride:

  • Lake Calhoun, Minneapolis
  • Como Lake, Saint Paul
  • Medicine Lake, Plymouth
  • Powderhorn Lake, Minneapolis
  • Carver Lake, Woodbury
  • Sand Creek, Jordan

44 lakes and rivers were added in 2014 to the draft list due to chloride contamination. You may have heard of a study by the University of Minnesota in 2009 on metro-area lakes and chloride. Every winter, 350,000 tons (700,000,000 pounds) of salt is used in the metro for de-icing and 70% of the salt applied stays in the area, polluting our lakes, river and streams.

Why does this happen?

One of the waterways added this year to the draft list is more than likely in your backyard, near your work or one of your property’s stormwater drains to that basin. When we apply salt as a deicer, it works because as it dissolves into the melting snow or ice, it lowers freezing point of that water. Allowing it to evaporate or run into our stormwater system.

Any salt that is applied eventually runs into the lakes, rivers and streams by spring. One teaspoon of salt permanently impairs 5 gallons of water. There is no natural way to remove the salt from the water. The salty water is less buoyant than the surrounding water and sinks to the bottom of our lakes and rivers and stays there.

Why should you care?


Carver Lake, Woodbury

Chloride levels were virtually non-existent in our waterways as recently as the 1960s. In the last 22 years the chloride levels have increased dramatically with our increase in use of salt as a deicing agent.

As we said before, one teaspoon of salt permanently impairs 5 gallons of water. The 2009 UofM study concludes that concentrations of salt in fresh water of one teaspoon to 5 gallons of fresh water is extremely detrimental to aquatic life,

decreasing the biodiversity in wetland areas, altering the development of wood frogs, decreasing the number and types of fish available, and increasing mortality rates of organisms that rely on an aquatic system.

If left unchecked, chlorides will also begin to affect our drinking water supply not only by changing the taste but dramatically increasing the cost. The only way to remove salt from water is reverse osmosis.

What can we do?

  1. Take responsibility. This is a problem that no one is going to solve on their own. The entire Commercial Real Estate and Property Management community needs to embrace this major issue and work to lower salt use on properties.
  2. Excess salt on sidewalk

    Excess salt on sidewalk

    Reduce use. Salt use is always going to be necessary to maintain safe properties. However, currently we use significantly more salt on our properties than is necessary. There are many simply ways to reduce the amount of salt used on your properties. Here are 8.

  3. Learn. The MPCA is taking an active role in teaching ways to reduce salt use on properties. Attend one of their free classes.
  4. Lead. The commercial property management community has an unique opportunity to lead the way in reducing the damage caused by salt use to our waterways. Take this opportunity to adjust your winter specifications and hold your providers accountable to maintaining safe and environmentally friendly properties this winter. It is up to us!