Press Release

A Mild Winter Is Not Enough to Combat Road Salt Pollution in D.C. Area Streams


Gaithersburg, MD – With winter firmly in our rear-view, many of us are thinking warm thoughts about the start of summer, even while practicing “social distancing” amid the coronavirus outbreak. Unfortunately, Izaak Walton League volunteers are finding dangerous levels of road salt (sodium chloride) in streams across Washington D.C. and its suburbs that will affect local 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. 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. Despite an extremely mild winter, Salt Watchers across the Washington D.C. region found multiple hotspots for road salts.

Of 222 Salt Watch results submitted in Maryland, Virginia, and Washington D.C.:

  • 18% of the results yielded high readings (over 100 ppm)
  • Of the high readings, 33% were toxic (over 230 ppm)

Volunteers included members of the Izaak Walton League, Neighbors of the Northwest Branch, the Muddy Branch Alliance, Arlington Regional Master Naturalists and other master naturalists, local teachers, Fairfax County Parks, Audubon Naturalist Society volunteers, and Virginia Save Our Streams water quality monitors (including from the Reston Association, Goose Creek Association, and NOVA Soil and Water Conservation District). The Izaak Walton League was selected as a 2020 Environmental Award Winner by the City of Gaithersburg for the excellent efforts with Salt Watch.

Road salt contamination is a water quality issue that researchers and government agencies around the country are trying to understand and solve. Salt Watch volunteers are important contributors to this effort.

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

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.