Stormwater and Salt: a Difficult Balance

Did you know that the salts used on our roads and driveways can have harmful effects on Maine’s lakes and rivers?

Although using salt and other chlorides is necessary for public safety, there’s an environmental cost associated as well. Stormwater runoff from storms and melting snow can carry chlorides and other pollutants from the ground right into our storm drains and ultimately streams, lakes, and rivers. The water that enters storm drains is rarely treated before it enters nearby water bodies!

When exposed to chlorides, water bodies can become uninhabitable for fish and dangerous for nearby wildlife that depends on the water to live. Unfortunately, more and more streams and rivers are becoming contaminated each year! Fortunately, you can help. Here are some tips to reduce your chloride use this winter.

  • Less salt is actually better. Most ice melt blends will have recommended use amounts right on the packaging– and most of the time it’s less than you’d think. A single coffee mug full of salt, applied carefully, can easily be enough for a full driveway.
  • Not all salts work the same way. If it’s really cold outside, your salt may not be working, so applying more won’t help. Each type of salt has a different temperature range– for sodium chloride (the least expensive and most common salt), at anything below 20°F the salt will be less effective, and the chemical stops working altogether at 15 degrees. The salt most effective at lower temperatures is calcium chloride, but be careful because this chemical is highly corrosive.
  • Salt before the storm. If you have to salt, do it before the storm rather than after. One golden rule of road maintenance is that it’s always easier to prevent anti-ice than de-ice. Any salt you apply before a storm can easily be several times more effective than salt applied after the storm.  
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Shovel first, then salt.

Shoveling before you salt can reduce the amount of salt you need to use. Save your salt to break up ice rather than using it on snow that you can remove without any help.