Road salt keeps us safe on roads and sidewalks during the winter months. Towns, cities, businesses, and individuals dump roughly 10-20 million tons of salt every year, depending on the winter weather conditions. As snow melts or rain falls, that salt gets washed into our storm drains, our streams, and even into our drinking water.

In 2017, a Clean Water Fellow at the  Izaak Walton League of America  noticed a huge pile of salt left by a salt truck sitting directly next to a storm drain. That salt was headed right for the Muddy Branch, a small stream that travels through Maryland and feeds into the Potomac River. He contacted local government agencies to try and address the problem. He quickly discovered that the world of road salt is a complicated one and that its effects on our waterways are not well known or well studied. Inspired by the success of the League's Save Our Streams community science program, IWLA staff launched Salt Watch to mobilize community scientists to monitor chloride (salt) levels in local creeks and streams.

Since 2018, volunteers from 24 states have submitted over 18,000 chloride readings. Partner groups like the Pennypack Ecological Restoration Trust and the Minnesota Pollution Control Agency are using Salt Watch to make local change.

And we keep growing each year. For the new season, we aim to partner with more local groups and, double the submissions we receive, and help volunteers advocate for smarter salt use in their community. You can join us and become a Salt Watcher too.

What's the problem with road salt?

Road salt is important for helping people travel safely in the winter. But road salt doesn't stay on roads: it washes off into streams, where it damages the quality of our drinking water and hurts critters that aren't adapted to life in salty environments. Learn more about the history of road salt, how much we use, and why it's a problem for stream health.


Okay, but don't we still need salt for safety reasons?

Yes, salt is needed. We are not pushing a “salt ban.” We hope that salt can be used in smarter ways and in smaller quantities moving forward. Alternative approaches include brine or sand application. Read more about alternatives to salt.


It's summer now, so I don't need to worry about road salt, right?

Unfortunately, no. Research finds that road salt can continue to pollute streams in the summer, and that aquatic life may be even more sensitive to salt in warmer weather. Learn why.


Visit the Izaak Walton League of America for more information on Salt Watch.


Visit the Clean Water Hub to see water quality data near you and across America.