Most people know it can be unsafe to drink unfiltered water out of a stream or lake, even if the water is visibly clear. This is true almost anywhere, including Adams County. Places where public swimming is encouraged are required to test the water to make sure it isn’t overly contaminated. But in Pennsylvania we have many waterways—more than 1,000 miles in Adams County alone— and most of them are not tested regularly.

We were curious about pathogen levels in other streams around Adams County where people like to fish, wade, swim, or otherwise play in the water. So in August 2022, thanks to a grant from the South Mountain Partnership, our corps of volunteers sampled stream water at 21 sites on 10 streams around the county and tested them for harmful pathogens.

We found that, with the exception of four sites, every location we tested was contaminated by E. coli at levels exceeding those recommended by the Pennsylvania Department of Environmental Protection for recreational use.

We’d like to acknowledge our partners and funders for this project: We’re working with Adams County Trout Unlimited, Friends of Toms Creek, and the Adams County Conservation District.

This project was financed in part by a grant from the Community Conservation Partnerships Program, Environmental Stewardship Fund, under the administration of the Department of Conservation and Natural Resources, Bureau of Recreation and Conservation. The grant was awarded through the South Mountain Partnership, with management oversight by the Appalachian Trail Conservancy.

We are a partner of the South Mountain Partnership, an alliance of organizations working to preserve and enhance the cultural and natural assets of the South Mountain Landscape in Central Pennsylvania. To learn more about the South Mountain Partnership, please visit www.southmountainpartnership.org

Testing in the two following years (2023 & 2024) confirmed our results and added to them. We now know that much of the fecal matter contamination comes from humans, and in at least one location, cattle. In 2024 we also found that one site had improved since 2022, namely Toms Creek at Carroll Valley Park. This location was found to be “attaining” recreational use in August of 2024.

The Environmental Protection Agency (EPA) estimates that at levels of E. Coli above the “Attaining Recreational Use” threshold indicate enough risk that between 3 & 4% of people interacting with the water will be sickened by it. The symptoms can range from very mild, such as a slight case of diarrhea, to severe.

Our advice remains to avoid drinking untreated water from our waters, and avoid exposing open sores or cuts to the water. Wading barefoot in a stream can be risky because a sharp rock or piece of glass can easily cut your foot and provide a pathway for pathogens to get into your bloodstream. Essentially all of the board members of WAAC fish, wade, and/or swim in our waters regularly, so we do not want to be overly alarmist about this. Our main goal is that people be aware of the potential hazards.