Volume 30 Issue 4, Fall 2025
by Amy Ulland, Stream Monitoring Coordinator
Loudoun Wildlife requested that these open salt bags at a local business be cleaned up. Each bag can permanently pollute 10,000 gallons of water — the amount in a residential swimming pool! Photo by Amy Ulland
When winter storms arrive, many of us instinctively reach for the salt bag to keep our driveways and sidewalks safe. But what we put on the ground doesn’t just stay there. Every crystal of salt eventually washes into nearby streams, where it permanently pollutes the water, harming fish, amphibians, insects, and other wildlife that depend on clean, fresh water.
The numbers are startling. Just 1 teaspoon of road salt is enough to permanently pollute 5 gallons of stream water. Once salt is in our waterways, there’s no easy way to remove it. By being “smarter salters,” we can balance winter safety with protection for our environment.
5 Simple Steps for Smarter Salting
- Shovel first. Salt is designed to melt ice, not snow. Shoveling or sweeping before salting reduces how much you’ll need — and sometimes eliminates the need altogether.
- Measure, don’t dump. A little goes a long way. Just 12 ounces (about the size of a coffee mug) is enough to treat a 20-foot driveway or 10 sidewalk squares. Using more won’t speed up melting; it just increases pollution.
- Use it only when needed. Before salting, ask, “Is it really necessary?” On a sunny day, cleared pavement may melt naturally without any help.
- Sweep up leftovers. After the storm, check your driveway and sidewalks. If salt remains once the ice is gone, sweep it up and store it to use again. This simple step keeps salt out of storm drains and out of our streams.
- Report excess salt. If you see large piles left on roads, sidewalks, or parking lots after a storm, report them to your town or county. Alerting public works crews can prevent thousands of gallons of water from being polluted.
Why It Matters
Excess salt upsets stream chemistry, threatening benthic macroinvertebrates — aquatic insects, crustaceans, snails, and other small creatures that keep streams clean and recycle nutrients. These organisms form the base of the food web, feeding fish, birds, and amphibians. Healthy fish populations in turn support other wildlife, recreational fishing, and overall ecosystem balance.
Because benthic macroinvertebrates are so central to stream life, they’re also Loudoun Wildlife’s primary way to monitor stream health: Changes in their diversity and abundance reveal when water quality is in trouble. When these species decline, the effects ripple up the chain, impacting waterfowl, mammals, and even people who rely on clean water.
Salt also seeps into groundwater, threatening drinking supplies, and damages roadside vegetation, soils, and trees. In Loudoun County, where creeks and rivers feed the Potomac and Chesapeake Bay, our choices have far-reaching downstream impacts.
Salt Watch volunteer Will Bassett tests chloride levels at Town Branch while a Great Egret looks on. Photo by Adrienne Bassett
Salt Watch: Community Science in Action
Now in its fifth season, Loudoun Wildlife Conservancy’s Salt Watch program — run in partnership with the Izaak Walton League of America (IWLA) — has grown into one of the largest in the country. Thanks to IWLA’s generous support, our volunteers receive free test kits to monitor chloride levels in streams. Chloride is the chemical in road salt that dissolves in water, and elevated levels are a clear sign of salt pollution.
Year-round, Loudoun Wildlife Salt Watchers collect samples monthly and after major winter storms, building a dataset that reveals both seasonal trends and pollution spikes. Locally, we monitor more than 80 stream sites and contribute about 15 percent of all Salt Watch data nationwide. This information is used at both the local and national levels to pinpoint pollution hotspots, raise awareness about the relationship between road salt and stream health, and inform scientists and policymakers working on solutions.
We’re always looking for more monitors and stream sites, and Salt Watch is easy to jump into. No experience is needed; training and free test kits are provided. It’s family-friendly, fun, and a rewarding way to connect with your local creek while giving back to the environment.
You can make a difference right at home: shovel before salting, measure carefully, skip salt when it isn’t needed, sweep up leftovers, and report excess piles. Small steps like these protect wildlife and water quality while keeping your walkways safe.
Join Loudoun Wildlife Conservancy’s Salt Watch team. Contact Amy Ulland (aulland@loudounwildlife.org) for more information.