Be Saltwise in Winter

Tackle snow and ice while protecting the environment 

Did you know using salt on walkways, driveways and roads is harmful to our environment? That includes sources of drinking water and the pipes and pumps needed to supply water to our customers. 

Once the ice and snow melt, the salt doesn’t go away. It seeps into the ground and wells, and travels with stormwater into streams, wells and drinking water reservoirs. It also corrodes pipes.  

It only takes 1 teaspoon of salt (sodium chloride) to permanently pollute 5 gallons of water to a level that is toxic to freshwater ecosystems. Once that salt is in the water, it does not dissipate.

Damage Salt Causes 

  • Harms aquatic animals and plants in local streams 
  • Pollutes soil and water 
  • Damages buildings  
  • Corrodes vehicles, pavement and pipes 

WSSC Water monitors the water in our Patuxent River reservoirs as well as the Potomac River, the source water for our Patuxent and Potomac Water Filtration Plants.  

Sodium chloride levels in WSSC Water’s Patuxent River reservoirs have been steadily increasing and, if the trend continues, could pose a problem in the future. 

Runoff directly upstream from the Potomac Plant has an impact.  

Over the last few years, we’ve noticed increased levels of salt in the water entering both water filtration plants. Peaks in chloride coincide with the winter months and are higher in years where there are more winter weather events. 

We have also noticed an increase in sodium levels in our T. Howard Duckett Reservoir.  

 What is the impact on human health?

Salt in drinking water can be a health threat to people on sodium restricted diets because of concerns about high blood pressure.  The Environmental Protection Agency (EPA) has published a drinking water health advisory level (not to exceed 20 mg/liter) for people on severely restricted sodium diets. Sodium levels in WSSC Water’s Patuxent River drinking water reservoirs have been steadily increasing and, if the trend continues, the average sodium level in the reservoirs may exceed the drinking water advisory level within 10 to 15 years. 

  • Patuxent River Average:  12.87 mg/L.
  • Potomac River Average:  17.60 mg/L.

More salt isn’t always best. Scatter deicer so there’s space between the grains and sweep up any that is left over after a winter weather event.


Do your part to keep excess salt out of local waterways.  

  1. Shovel snow and clear the pavement before snow turns to ice 
  2. Only use if there is ice  
  3. Apply the least amount of deicer necessary 
    A 12-ounce coffee mug full of salt is enough to treat a 20-foot driveway or 10 sidewalk squares 
  4. Scatter the deicer and leave space between the grains  
  5. When pavement temps drop below 15 degrees, salt won’t work. 
  6. Consider using sand for traction 
  7. Choose a deicer with calcium magnesium acetate -- This is the most eco-friendly deicer 
  8. Do not pretreat. Salt placed on the pavement before a snowfall does not melt it or prevent it from sticking. Additionally, weather can change and, depending on the event, you may wind up having to apply twice the amount of salt if the first batch is covered up.  

Read more homeowner tips from the Carey Institute of Ecosystem Studies here

What are state and local agencies doing about this?

Over the past five years, the Maryland State Highway Administration has reduced its overall salt usage by half.  See what they and the Maryland Department of the Environment are doing to manage road salt treatment here.

If you’d like to read the latest science on the environmental and health impacts of road salt pollution, check out this report by the Carey Institute for Ecosystem Studies.

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