Sodium Chloride (Road Salt) Monitoring
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Road salt, most commonly in the form of rock salt (sodium chloride), is used extensively during winter months to keep people safe by melting ice on roads and sidewalks. However, excess salt doesn’t disappear after it is applied. It can end up in streams and rivers, and even in your drinking water. Excess salt concentrations in streams and rivers can harm freshwater fish and insects that can’t survive in salty water. While sediments and nutrients can be filtered and treated in the municipal water supply easily, it is more difficult to remove salt. Most water treatment plants are unable to filter out high levels of salt, so it can end up in your tap water. The same holds for those that draw from wells. While sodium is not harmful to most in low levels, it could impact those who have dietary sodium restrictions in concentrations over 100 mg/L. Additionally, chlorides, while not posing a direct health risk, can, in levels exceeding 250mg/L, corrode the inside of your pipes leading to plumbing damage and the leaching of harmful metals, such as lead and copper, into your drinking water.
The Izaak Walton League of America (IWLA) Salt Watch program aims to measure the impact of road salt pollution on aquatic ecosystems nationwide and advocates for more responsible salt application. As a Salt Watch partner organization, Pomperaug River Watershed Coalition piloted a sodium chloride water quality testing program in the winter of 2023-2024 to monitor the level of road salt pollution in the Pomperaug River Watershed. Monitoring sites were selected to test for road-salt contamination from November to March based on their proximity to impervious (paved) areas. This program will be expanded to include 8 sites this winter (2024-2025) to help identify areas in the watershed that may need to be salted more responsibly in the future.
What Can I Do?
The amount of salt being applied to roads is increasing each year. The best way to mitigate road salt pollution in your community is to simply use less salt while still maintaining public safety.
For Residents:
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Be informed about the impacts of salt on your watershed and drinking water. The Pomperaug River Watershed Coalition is monitoring the presence of road salt pollution by testing for chloride in the watershed’s streams and rivers. Residents who own wells should test their water regularly and make informed decisions about treatment options.
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Start at home by reducing the amount of salt applied to your driveway - Remember, all you need is 12 oz of salt for every 20 feet of pavement!
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Educate those you know in your family and community about the impacts of road salt.
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Take action by visiting Salt Watch (iwla.org) and taking the Salt Watch Pledge. Those who take the pledge will be sent a free kit with everything you need to test your local streams for road salt.
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For Municipalities:
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Employ best practices by only salting where needed and installing application regulators on spreading vehicles to control how much salt is being applied.
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Consider brines over rock salt. Pre-treating roads before a storm with a brine solution can prevent snow and ice from bonding to the pavement. This makes plowing easier and reduces the amount of salt that needs to be applied.