Using Sidewalk Salt Responsibly
Salt can make sidewalks and roadways safer, but it also harms pets and wildlife, pollutes drinking water, and corrodes buildings, cars and bridges. Use salt wisely by following these steps:
1. Shovel
Clear walkways before snow turns to ice, and before you apply salt. The more snow you clear manually, the less salt you’ll need.
2. Select
Salt doesn’t melt ice if the pavement is below 15 degrees, so use sand for traction when it’s too cold, or choose a different de-icer.
3. Scatter
Use salt only where it’s critical. When you apply salt to pavement, leave plenty of space between granules. A 12-ounce coffee cup of salt is enough to cover 10 sidewalk squares or a 20-foot driveway.
4. Sweep
Clean up leftover salt, sand, and de-icer to save and reuse as needed.
The high cost of salt
Minnesota uses about 350,000 tons of salt a year in winter maintenance. That costs tax payers 25 million dollars a year, but the damages are estimated at 375 million dollars per year. That much salt permanently pollutes more than a quarter trillion gallons of water, affects our lakes, streams and ground water, has lasting impacts on roads, bridges, buildings, and vehicles, and can harm pets, people, wildlife and plants.
Salt and Deicer Comparison
Virtually all salt and deicer compounds and blends are damaging to the environment as well as harmful to concrete, metal and other materials. Some will work in lower temperatures than others. Here is a comparison of some common deicers and their various properties.
| Melting Agent | Lowest Melting Temp.* | Things to Know |
|---|---|---|
| Urea | 20°F | Promotes algae growth in waterways; over-application can harm plants; pet-safe; slow-acting |
| Sodium Chloride (NaCl) | 15°F | Harmful to plants; harmful to concrete; very corrosive to metal; cheap and abundant |
| Magnesium Chloride (MgCl2) | -10°F | Harmful to plants; corrosive to metal; relatively high cost |
| Potassium Acetate (KAc) | -15°F | Can cause surface slickness; lowers oxygen levels in waterways; biodegradable; relatively high-cost |
| Calcium Chloride (CaCl2) | -20°F | Corrosive to metal; leaves slimy residue; less harmful to concrete |
| Sand | No melting | Provides traction only; potential pollutant; can be swept up and re-used |
Comparison table courtesy MWMO
Learn more about state and metro-wide efforts to protect lake, streams and groundwater from chloride contamination: www.pca.state.mn.us/roadsalt
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