This story comes from our partners at WHYY.
During sunny summer afternoons, children play and revel in a splash park at the Ferko Playground in the Juniata neighborhood in North Philadelphia.
But during weeks of intense rainfall, their frolicking is disrupted by a nearby waterway that erupts with raw sewage. Beyond the park and rec center, a colossal 20-foot concrete hole is anchored at the tree-lined Frankford Creek.
During heavy rains, that sewer tunnel spews a torrent of dirty stormwater and raw sewage. The putrid smell permeates the air, near where children play around the corner. The idea of hiking in nature near the creek after a storm seems out of reach.
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“That is a violent and powerful force, and when you have that kind of situation, it means that you can’t really have people and children safely at these sections of the creek,” said Justin DiBerardinis, executive director of the nonprofit Tookany/Tacony-Frankford Watershed Partnership.
“In 2026, in Philadelphia, it shouldn’t be that way,” he said. “We should not have sewage flowing through people’s neighborhoods.”
The Frankford Creek is one of several waterways in Philadelphia that are often contaminated by untreated waste because of outdated sewer systems that make way for stormwater and sewage to spill into rivers and creeks.
Philadelphia has made great strides to reduce these so-called “combined sewer overflows” by using nature-based solutions like rain gardens to soak up stormwater.
However, as the city’s green stormwater infrastructure initiative, Green City, Clean Waters, hits its 15th year, waterways like the Tacony and Frankford creeks continue to fail to meet state and federal water quality standards.
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This summer, the city began studying the potential for a decade-long infrastructure project: a mammoth underground tunnel system that would capture millions of gallons of stormwater and sewage before treating them at sewer plants.
If the city decides to move forward, the “gray” stormwater infrastructure project could help the city meet federal Clean Water Act standards.
“You are not going to green infrastructure your way out of having any [combined sewer overflows] in Philadelphia,” DiBerardinis said.
A ‘disgusting concoction’
Swimmable, fishable waterways have long been the goal of the Clean Water Act, passed in 1972. But more than 50 years after its passage, older cities like Philadelphia struggle to reach that level of cleanliness because of outdated sewer systems.
Unlike modern infrastructure, which utilizes separate piping systems, older sewer systems send stormwater and sewage through the same underground pipes.
During heavy rains, these older systems can overflow, spilling untreated sewage into the region’s rivers and streams. This contaminates waterways with bacteria and makes them unsafe to recreate in. These overflows can also exacerbate localized flooding.
“If Philadelphians think about all the things you see in the street that wash down the drain — like litter, trash, oil, pesticides — that’s getting combined in the sewer system with the things that we put down our toilets and sinks, creating this disgusting concoction,” said David Masur, executive director of the nonprofit PennEnvironment.
The Philadelphia Water Department in 2011 launched Green City, Clean Waters, a 25-year-plan, to reduce the amount of sewage entering the city’s waterways by using green infrastructure and expanding stormwater treatment capacity. It’s part of a consent agreement with the U.S. Environmental Protection Agency and is enforced by the Pennsylvania Department of Environmental Protection.
The water department said more than 1,000 projects have helped reduce combined sewer overflow volumes by more than 3 billion gallons annually — surpassing its 15-year benchmarks. The city is often credited with being the first U.S. city to lean heavily into green stormwater infrastructure as its mainstay.
“I think what we have achieved in Philadelphia, we should be really proud of, because no other city has brought a green stormwater infrastructure system or program to scale in the way that we have done,” said Glen Abrams, deputy commissioner of communications and engagement at the Philadelphia Water Department.
The city has reduced combined sewer overflows by utilizing natural solutions like rain gardens and tree and subsurface trenches that soak up and filter water, and by expanding treatment capacity at sewage plants.
Nature’s solution
Morris Park in Philadelphia’s Overbrook neighborhood is just one location where rain gardens, and an infiltration and storage trench system, are collecting stormwater and diverting it from the sewer system.
“To me, this is nature,” said Daniel Schupsky, a community outreach specialist at the water department, as he walked along a rain garden at the park.
“It looks wild to some people, it is not a Victorian garden, it is not a rose garden, but this is the way that nature grows, and we are planting natives in here because they have the best chance for survival, and it supports local pollinators, and it provides habitat, all while managing stormwater.”
The project diverts more than 174,000 gallons of stormwater during typical storm events, according to the water department.
Green stormwater infrastructure, along with improved sewer systems and initiatives that reduce inlet clogging, have worked in conjunction to reduce combined sewer overflows overall, according to city officials.
However, more than 12 billion gallons of raw sewage continue to spill into local waterways each year, on average, according to reports. The amount of overflows released into waterways can be lower or higher, depending on how wet or dry a year is.
A single outfall in the Tacony Creek, for instance, is responsible for an average 1.4 billion gallons of annual combined sewer overflows into the waterway. In the Frankford Creek, one outfall alone is responsible for an annual average of 878 million gallons of overflows.
Tina Ridgway helps organize afterschool programs and summer camps at the Ferko recreation center. She likens the combined sewer overflows in the Frankford Creek to waiting in line at a port-a-potty.
“We’ll do walks on the trail, and you even smell it back by the creek,” she said. “It is not healthy for people to be smelling that.”
The city said reducing combined sewer overflows in the Tookany/Tacony-Frankford watershed is challenging because there’s not enough available land to expand stormwater projects, and storms have become more intense than green stormwater infrastructure can handle. Scientists say climate change will only make rainfall heavier in the coming years, and increase the risk of combined sewer overflows.
“We’re seeing the flooding in these really high-intensity rains where you get a lot of rain in a short amount of time,” Abrams said. “Green stormwater infrastructure, for the most part, is designed for our more common rains.”
From green to gray infrastructure
Philadelphia must lean into gray stormwater infrastructure to meet Clean Water Act goals, Abrams said. The city is evaluating the feasibility of a 5- to 8-mile tunnel system that, if approved, would store stormwater 100 to 150 feet underground and reduce sewer overflows.
The so-called “Wingohocken Wet Weather Tunneling Plan” is just one step the city could take to expand gray stormwater infrastructure in combined sewer overflow hotspots.
For instance, the city plans to reduce combined sewer overflows in Cobbs Creek by more than 100 million gallons a year by retrofitting an existing flood-relief conduit into a temporary combined sewer overflow storage facility. The system currently discharges more than 150 million gallons of dirty stormwater and sewage into the waterway, according to the water department.
These projects are a stark contrast from the green stormwater infrastructure championed in Green City, Clean Waters. However, Abrams said the initiative was never intended to be one-size-fits-all.
“We weren’t moving away from gray infrastructure, it was adding green infrastructure on top of our existing system,” he said. “We did a really good job of promoting green stormwater infrastructure because it was brand new and a lot of people didn’t understand it, but conventional infrastructure was always a part of the plan.”
If the project moves forward, the city believes it will reduce combined sewer overflows by 400 million gallons a year.
Abrams said it would also help to reduce serious flooding issues in Germantown, which is partly caused by infrastructure practices that began in the 19th century.
In the 1800s, the city began to cover up North Philadelphia’s Wingohocking Creek and its watershed, which eventually became part of the city’s sewer system. The now-extinct Wingohocking flowed into the Tacony and Frankford creeks.
Creek encapsulation occurred throughout Philadelphia to address pollution and what was later understood as waterborne disease.
The pipes where the Wingohocking once flowed aren’t large enough to carry stormwater during heavy rains. The problem is exacerbated by the low-lying area of Germantown, and sewers become backed up. Stormwater, which has nowhere to flow into, often runs down the neighborhood’s inclined streets.
Jill Saul has lived in Germantown for 30 years. During heavy rains, she said the water runs past her home like a river. The most devastating effect was in 2011, during the aftermath of Hurricane Irene and Tropical Storm Lee, when the area was inundated with floodwaters; one resident drowned in her car.
It was trash night, and garbage cans floated down the street, clogging inlets with debris. The water rose, flooded Saul’s car, and filled her basement.
The washing machine and fridge, as well as a bench that her husband and son built for a school project, floated around the basement.
“I was standing at the door, looking down into the basement, watching the water rise over each step and thinking, ‘Oh my God, is it going to breach and come into the living room, into the dining room?’” she said. “It didn’t, thank goodness. So, we got lucky. Other people weren’t so lucky.”
A pencil line still marks the wall where Saul’s husband recorded 4 feet of water.
Upgrading aging infrastructure
The potential tunnel project wouldn’t be complete for at least another decade, and it’s expensive. Abrams said though the planning study is advancing, the potential project is far from having a completed design or cost estimate.
However, in Washington, D.C, a 5.5-mile tunnel currently under construction, as part of a system of tunnels, to reduce combined sewer overflows in the Potomac River costs $819 million for the primary design-build contract alone.
Philadelphia residents like Tina Ridgeway are concerned a project of this scale would impact water bills.
“Everything the water department does, they always add on the little taxes to everyone,” she said. “It’s already hard to live. Everything’s expensive as it is.”
Abrams said meeting their obligations while keeping bills affordable is one of the biggest challenges the water department has to grapple with. The U.S. needs at least $630 billion in wastewater and stormwater infrastructure improvements over the next 20 years, according to the EPA.
“Rates have increased, we’re not making a profit, we only request the amount of money that it takes to operate the facility and pay debt service to finance our capital program,” he said. “But, as we have more and more responsibilities, the need to reinvest in aging infrastructure, balancing all of that can be a challenge.”
Environmentalists like Masur say the tunnel could be a good solution. In cities from Milwaukee to Chicago, deep tunnel systems have reduced millions of gallons of combined sewer overflows.
Last year, the Chicago River opened to swimming for the first time in 100 years. The city estimates its tunnel system has reduced combined sewer overflows by 85%. Still, the system isn’t perfect. This year’s Chicago River Swim was canceled because of severe weather and the likelihood of a combined sewer overflow event.
Masur argues Philadelphia is moving at a slower rate than other major cities, and said regulations aren’t strict enough.
The city contends it’s held back by a number of challenges, such as the densely built landscape of Philadelphia, the length of time it takes to build projects, and juggling other demands like removing lead pipes and filtering drinking water.
A large portion of combined sewer overflows in Philadelphia are isolated to 10 of the city’s more than 160 outfalls, according to PennEnvironment. Masur said a more surgical approach focused on those select outfalls would make a significant difference.
“Philadelphians, we’re all attached to our waterways. We love the Delaware River. We love to walk or ride our bikes by Boathouse Row, or walk along Cobbs Creek or the Frankford Creek,” he said. “I think more people would want to swim, fish and boat on them if they felt the water was cleaner and safer.”
