Press Release

Despite a Mild Winter, Evidence of Road Salt in Philadelphia-Area Streams Remains


Gaithersburg, MD – With a mild winter firmly in our rear-view, many of us are thinking warm thoughts about the start of summer, even amid the coronavirus outbreak. Unfortunately, Izaak Walton League volunteers found dangerous levels of road salt (sodium chloride) in Philadelphia-area streams that will affect water quality for many months to come.

The Izaak Walton League created Winter Salt Watch to give volunteers the tools to identify excess road salt in their community streams. The League distributed test kits to about 1000 volunteers this winter, and those volunteers documented salt levels in streams across 19 states.

Kevin Roth, from the Pennypack Ecological Restoration Trust, thinks back to when his group began participating in Salt Watch. When monitoring in 2018, their network of in-stream remote sensors showed chloride triple after a surprise early snowstorm when the local township’s public works department did not salt at all. Roth and his team quickly realized that a major part of the problem was salt application by private businesses and homeowners. They learned about the Izaak Walton League’s Salt Watch program and saw it as a great opportunity to engage the public and their volunteers on chloride pollution. “We saw it as a way for regular homeowners to learn that a) this is a problem, and b) you can do something about it” said Roth.

Despite a mild winter in some areas of the country, high levels of chloride were found in streams around nine metropolitan areas – not just occasional spikes, but consistently high levels of chloride. How much is too much? Freshwater streams should have low to no salt content. Levels above 100 parts per million (ppm) are beyond what could be considered a naturally occurring concentration of salt, and above 230 ppm is toxic with prolonged exposure. Salt Watchers were active around Philadelphia and its suburbs, and those dedicated volunteers found the following results:

Of 81 Salt Watch results submitted in the Philadelphia Metro Region:

  • 37% of the results yielded high readings (over 100 ppm)
  • Of the high readings, 20% were toxic (over 230 ppm)

These results are particularly alarming, since the Philadelphia winter was mild with very few winter weather events. This suggests that road salt pollution has staying power and can impact aquatic life and drinking water for years after the salt hits the pavement. It also suggests that smarter salt application could make a big difference.

Volunteers for this effort included the Pennypack Streamkeepers, Tookany/Tacony-Frankford Watershed Partnership, Darby Creek Valley Association, River Watershed Initiative, Lower Merion Conservancy, Wissahickon Valley Watershed Association, Ambler Environmental Advisory Council Master watershed stewards, and local teachers.

Road salt contamination is a water quality issue that researchers and government agencies around the country are trying to understand and solve. Having site-specific data on chloride levels is the first step in advocating for best practices to protect drivers and clean water. These best practices include:

  • Tailoring salt-application strategies based on the weather and the salt product being used
  • Using calibrated salt spreaders on salt trucks and road temperature sensors
  • Training and certifying snowplow drivers and contractors who maintain walkways, parking lots, and service roads
  • Understanding how salt levels affect corrosion of drinking water pipes and how to prevent corrosion

This is just the beginning of the fight against road salt pollution for the Pennypack Ecological Restoration Trust and their volunteer base. “This year we are starting with the community and getting them to tell their friends and neighbors,” says Roth. Next, they will be engaging and educating businesses and local government entities to raise awareness and create change when it comes to road salt practices.

Visit for more information on this effort or to request a kit. Visit for details on state and local best management practices. Salt Watch is open all summer long and is an excellent activity to do solo.


Founded in 1922, the Izaak Walton League of America protects America’s outdoors through education, community-based conservation, and promoting outdoor recreation.