Let’s Talk About Poop: E.coli in the delaware river

Lucia Osborne, Delaware Bayshore Program Director

Warning: Toilet Talk Ahead!

map of E.coli levels in the Delaware River

Everybody poops! It’s a natural function and the body’s way of getting rid of excess waste. Our poop comes in a variety of sizes, colors, and smells, but for the most part, it’s all healthy and normal and bears little consequence on the rest of the world. It’s what happens after we flush the toilet that impacts our water, communities, and ecosystems.

​A recent report from our partners at PennEnvironment showed that the Delaware River frequently has unsafe levels of E.coli, a bacteria that’s commonly found in poop, in the stretches of the river that flow through Philadelphia. That’s interesting because Philadelphia has a Combined Sewer Overflow (CSO) system. It’s an old style of water utility where the sanitary lines – the pipes that transport wastewater from where people live, work, and poop – are connected to the stormwater lines – the pipes that carry rainwater that runs off of our streets and buildings. When it rains too much, the system gets overwhelmed and raw sewage overflows into our waterways, and sometimes backs up into people’s basements and streets.  

The Philadelphia Water Department (PWD) is responsible for 164 combined sewer outfalls in the city. Collectively, these outfalls released over 12 billion gallons of sewage pollution into the Delaware River and the streams that feed into it. So, it’s not surprising that these same areas are reporting high levels of E.coli.

​This is a serious water quality problem. It makes our rivers and streams unsafe for human contact, and can cause serious gastrointestinal illness in people who swim, kayak, or accidentally ingest this water. The high levels of bacteria can also reduce oxygen levels in the water, making it harder for fish and other aquatic life to survive. And, if the sewage pollution backs up into people’s basements or neighborhoods, it can damage their personal property and make people sick.

A common counter argument from the Water Department is that upstream pollution, like animal waste running off of farms, is the likely culprit. Also, we acknowledge that correlation is not causation. But if upstream runnoff was really the culprit, you’d expect to see that in the data. Instead, concentrations of E.Coli are lower outside the City boundaries and then spike as soon as they reach the area where CSO outfalls begin. This leads to a reasonable conclusion that sewage pollution is a major part of the problem.

Furthermore, another report recently came out of the Delaware River Basin Commission. That report used DNA source‑tracking and found that the dominant source of bacteria in this stretch of the river was human derived (again that means human poop). This reinforces the conclusion that the contamination we are seeing is not simply the result of wildlife or farm runoff—it is human sewage entering the river because infrastructure is not keeping up with today’s population or climate realities. 

Outflow at Frankford Bridge in Pennypack

Currently, the City is on track to reduce sewage pollution down to 7 billion gallons per year by 2036. We think that they can do better. Many other Cities, like Chicago and Portland, have found ways to cut sewage pollution down to close to zero. Even New York City has successfully implemented a series of underground storage tunnels and treatment plant upgrades to help reduce sewage pollution - they haven’t completely solved the problem, but the City at least acknowledges that they still have a long way to go.

​Solutions to this problem exist, and are not new or novel. What’s missing is the willingness of PWD to implement said solutions. The American Littoral Society is actively working to hole PWD accountable for a clean Delaware River. We are also researching solutions and funding methods to help move this issue forward. Stay engaged with us to keep learning about this issue and what you can do to help! ​

References: 
2025_WC_Assessment_Report_Delaware_Estuary.pdf 
NEW REPORT: Pennsylvania rivers and streams regularly test positive for harmful bacteria 

Video of overflow at Juniata Park (Tacony)

For more information on this issue, please see these news articles from a recent press event about E.coli in the Delaware River:

WHYY
Billy Penn Morning Round-up
Philly Citizen