'Potentially unsafe levels' of E. coli found in hundreds of Pennsylvania waterways, group says

Swimmers might want to think twice before taking a dip in Pennsylvania’s waterways, according to a report by an environmental advocacy group.

A report released Wednesday by the Philadelphia-based PennEnvironment Research and Policy Center found that 359 out of 653 monitored locations across Pennsylvania rivers — about 55% — had “potentially unsafe levels” of E. coli bacteria on at least one day during monitoring periods in 2024 and 2025.

Data also showed that almost 40% of monitored locations had potentially unsafe levels of fecal contamination on at least a quarter of the days on which testing took place.

“The rivers, lakes and streams that crisscross Pennsylvania are an invaluable part of our natural heritage, and each year millions of the state's residents and people, really from all over the globe, visit Pennsylvania's waterways to walk their shores, to kayak and paddle, to boat, to fish and swim, and especially this time of year,” the center’s executive director, David Masur, said during a virtual news conference Wednesday.

“Far too often, our streams and rivers are plagued with pathogens that can make swimmers, paddlers or even anglers sick,” he added.

Pennsylvania was one of 17 states included in the center’s national report, “Safe for Swimming? America’s Rivers and Lakes,” which tested water quality at more than 4,500 locations across the U.S.

In Pennsylvania, 39% of monitored sites had potentially unsafe levels on more than a quarter of their test days, PennEnvironment said, which is on the lower end among states in the report.

Ohio waterways ranked the highest, with 79% of sites showing unsafe levels more than a quarter of the time they were tested, followed by Missouri and Michigan.

In Allegheny County, monitoring systems were set up at at least 22 sites, and testing was conducted for five to six days, with the exception of milepost 4.3 on the Ohio River, located near McKees Rocks.

Seven of those sites recorded potentially unsafe levels of contamination every day they were tested.

Samples from the Monongahela River, collected near Baldwin, showed E. coli levels exceeding the Beach Action Value for health risks on five out of six days, according to the report.

The BAV is a water quality threshold set by the U.S. Environmental Protection Agency that public health officials use to trigger short-term swimming advisories or alerts at freshwater beaches. The threshold for E. coli is between 190 and 235 colony-forming units per 100 mL of water, according to the EPA.

“Pittsburgh's waterways should be places where folks can swim, fish, gather, and enjoy the outdoors without fear,” Pittsburgh City Councilwoman Erika Strassburger said in release. “When we see repeated E. coli exceedances, it raises real questions about whether people can safely use these spaces. We must continue the work to make sure our rivers and streams are clean, safe, and places that people feel good about spending their time in.”

The report pointed to several sources of pathogen pollution that can make swimmers sick, including outdated and deteriorating sewage systems.

For example, sanitary sewers can spill dangerous sewage that contains bacteria, viruses and parasites prone to causing disease in humans into local waterways if sewer lines become blocked or break when overwhelmed.

Combined sewer systems are also problematic because they’re designed to discharge raw sewage directly into nearby waterways during heavy rain events.

These problems are particularly evident in the Pittsburgh region, where the Allegheny County Sanitary Authority estimates its system overflows about 9 billion gallons of combined sewage in a typical year with average rainfall.

The authority was ordered to reduce its overflows by 8 billion gallons annually through a federal consent decree issued by the EPA in 2008. It was eventually modified in 2020 and established a deadline for the authority to develop a wet weather control plan by 2036.

Since then, Alcosan has begun a 10-year project that will establish a regional tunnel system that will allow three tunnels — the Ohio River Tunnel, Allegheny River Tunnel and Monongahela River Tunnel — to work together to capture and convey excess wet weather flows to the authority’s treatment plant on the North Side.

Construction for the Ohio River Tunnel began in June, and the remaining two tunnels are estimated to be completed by 2036.

“This project is an investment in the future of Pittsburgh,” city spokeswoman Molly Onufer said in June. “It will provide modern infrastructure, create jobs, protect our rivers and improve water quality for generations.”

Sprawling development and factory farming are two other main sources behind water pollution, according to PennEnvironment.

The addition of parking lots, roads and larger homes increases the flow of polluted stormwater into rivers, bays and coastal waters, researchers found. The problem is exacerbated when wetlands and forests that had once absorbed that rainfall are paved over.

Manure from large-scale livestock production can also be carried by rain into nearby waterways.

To protect and improve the quality of local waterways, Masur said local, state and federal government agencies should “dig deeper.”

That starts with investments in repairing and modernizing wastewater and stormwater infrastructure, protecting and restoring wetlands, preventing manure from entering rivers and lakes, and expanding water quality monitoring and public notification programs so people have access to timely information about water conditions, according to PennEnvironment.

“At PennEnvironment, we're confident that if our elected officials truly prioritize clean water, Pennsylvanians will be able to enjoy our great outdoor locations, enjoy great outdoor recreational activities like swimming, boating and fishing, all along the great rivers, lakes, and streams in the Keystone State for generations to come,” he said.

_____