winter salt watch logo


Last winter, people from around the country tested their streams for salt. The maps at the right show what they found: 31 watersheds tested by citizen scientists always showed normal, safe chloride levels, but high levels of chloride were found in 8 other watersheds that include metropolitan areas.

Repeated testing demonstrated that these metropolitan watersheds had consistently high levels of salt: 25% of test results were above the maximum level of salt considered tolerable for freshwater organisms (230 ppm), and an additional 31% were noticeably higher than levels of salt normally found in freshwater. Of the watersheds that tested high in chloride, the Lower Delaware and the Schuylkill in the Philadelphia metro area, the Middle Potomac-Anacostia in the Washington, DC, metro area, and the Clinton in the Detroit area showed abnormally high salt levels on more than half of their results.

Your efforts make a difference.

This spring, the Philadelphia Inquirer ran a front-page piece in its regional section highlighting Salt Watch results in streams throughout the region. The chloride levels around Philadelphia were especially high, with 23 tests measuring concentrations of 230 ppm or greater. One small stream had a chloride concentration of 800 ppm in March! League staff and local volunteers were interviewed for the story.

League staff were also interviewed by television and radio stations in Philadelphia. Listen to one of the radio interviews.

These media stories helped more people learn how excess road salt can create water quality problems. When more people understand the problems, we can work together to find solutions.

Thank you for keeping our streams safe!

Read more about what was learned from the 2018-2019 Winter Salt Watch season.


Get involved in this year's Winter Salt Watch



What Impacts Chloride graph info

Winter 2018-2019 Salt Watch Results

Salt Watch national

Salt Watch Up Close: Washington, DC

DC area

Salt Watch Up Close: Philadelphia, PA

Philadelphia area

Salt Watch Up Close: Midwest

Midwest