PHILADELPHIA, PA — Harmful bacteria were detected repeatedly in the Delaware River and waterways across Philadelphia and its suburbs during 2024 and 2025, with some Chester County monitoring sites reaching potentially unsafe levels on every day tested, according to a new analysis by PennEnvironment Research & Policy Center.
Along Philadelphia’s section of the Delaware River, elevated fecal bacteria levels were recorded at 37 of 43 monitoring locations, according to the report. Twelve locations exceeded potentially unsafe levels on every day they were tested.
Testing also found potentially unsafe levels on 73% of days sampled in Pennypack Creek, 57% in Poquessing Creek and 55% in the Schuylkill River.
The findings extended into the suburbs. In Chester County, monitored portions of Brandywine Creek and Big Elk Creek registered potentially unsafe fecal bacteria levels on 100% of testing days.
Crum Creek in Delaware County reached potentially unsafe levels on 66% of days tested, while Ridley Creek did so on 53%. In Bucks County, Neshaminy Creek recorded potentially unsafe levels on 26% of testing days.
Statewide, 55% of 653 monitoring locations recorded at least one day during 2024 and 2025 when E. coli reached levels considered potentially unsafe for swimming, according to PennEnvironment. About 39% of the sites reached potentially unsafe fecal contamination levels on at least one-quarter of the days sampled.
The results do not mean each waterway was continuously contaminated throughout the two-year period. The percentages reflect conditions on days when testing occurred at the monitoring locations included in the analysis.
Fecal indicator bacteria such as E. coli can enter waterways through sewage spills and overflows, stormwater runoff and failing septic systems.
Stephanie Wein, clean water and conservation advocate for PennEnvironment Research & Policy Center, argued that the frequency of the findings limits the public’s ability to safely use waterways for recreation.
“Too many days a year, the places where we want to cool off, paddle or cast a line are unsafe,” Wein stated.
The report follows a 2025 PennEnvironment analysis that estimated the Philadelphia Water Department releases an average of 12.7 billion gallons of untreated sewage and stormwater annually into the Delaware and Schuylkill rivers and their tributaries.
Lucia Osborne, Delaware Bayshore program director for the American Littoral Society, called sewage pollution “a serious public health issue that impacts both people and wildlife” and argued that other cities have demonstrated that the problem can be addressed.
Philadelphia Councilmember Jamie Gauthier, who chairs City Council’s Committee on the Environment, stated that she would continue working with the Philadelphia Water Department while seeking state and federal investment to improve recreational water quality.
PennEnvironment called for additional action by the city and other local governments to reduce contamination in regional waterways.
Support the local news that supports Chester County. MyChesCo delivers reliable, fact-based reporting and essential community resources—free for everyone. If you value that, click here to become a patron today.