The Philadelphia Water Department champions the goal of cleaner, healthier rivers and streams for Philadelphians and visitors alike. We also value the advocates who care deeply about protecting our waterways for generations to come. However, some characterizations of PWD’s work in the recent PennEnvironment report “Sewage Pollution in the Philadelphia-Camden Region” and associated webinar(s) do not fully reflect the complexity of managing and upgrading an aging urban sewer system while safeguarding public health and balancing affordability for ratepayers.

Combined sewer overflows (CSOs) are a real and longstanding challenge in older cities like Philadelphia. That’s precisely why, nearly 15 years ago, the City launched one of the most ambitious urban water quality programs in the nation: Green City, Clean Waters. PWD has worked tirelessly to implement water quality investments to benefit our communities and uses an innovative approach to achieving water quality improvements, creating the programs, policies, and tools necessary to facilitate a groundbreaking investment in Philadelphia’s waterways and communities. To date, we have met or exceeded all regulatory obligations set by the Pennsylvania Department of Environmental Protection (PADEP) and United States Environmental Protection Agency (USEPA) associated with this clean water program.

Proven Progress

Since the program began, Philadelphia has:

  • Reduced combined sewer overflow volumes by more than 3.08 billion gallons annually, exceeding regulatory targets
  • Achieved nearly 40% of the program’s long-term CSO reduction goal
  • Met or exceeded regulatory milestones established by the Pennsylvania Department of Environmental Protection and the U.S. Environmental Protection Agency

These reductions are measurable, verified, and ongoing.

Clarifying the Data

  • The statistics cited in Penn Environment’s materials include inferences drawn from PWD’s own reporting and reflect real challenges with combined sewer overflows (CSOs) in wet weather.
  • PWD has projects under construction that are expected to reduce another 600 million gallons of CSOs annually in the next 3 years. These projects include upgrades to regulator chambers, collections, conveyance and wastewater treatment facilities.
  • The 2009 CSO Long Term Control Plan Update (LTCPU) (also known as Green City, Clean Waters, or GCCW) was formally approved by the PADEP in a 2011 Consent Order & Agreement (COA), and USEPA in 2012 through the Administrative Order for Compliance on Consent (AOCC). These agreements were not the product of enforcement actions or violations; rather, they serve as regulatory mechanisms for approving the City’s CSO program and implementation approach.

Why This Challenge Exists

  • Philadelphia’s original sewer system was designed more than a century ago. It serves a 60-square-mile combined sewer area with 165 permitted outfalls across the Delaware, Schuylkill, Cobbs, and Tacony-Frankford watersheds — some of the most densely-built historic neighborhoods in the country.
  • Infrastructure planning and construction at this scale requires long lead times for:
    • Design
    • Permitting
    • Extensive engineering and environmental review
    • Federal and state regulatory coordination
    • Community engagement
    • Significant financial investment
  • Large-scale improvements, like storage tanks, tunnels, or sewer separation, cannot be implemented overnight — but they are being evaluated deliberately and responsibly.

Balancing Priorities

PWD must balance CSO reduction with other critical obligations, including:

  • Continually provide safe and reliable drinking water for nearly 1.6 million customers
  • Maintain and rehabilitate aging drinking water and wastewater infrastructure
  • Meet federal and state regulatory requirements across multiple programs
  • Respond to emergencies across the system
  • Maintain affordability for ratepayers

Approximately 20% of Philadelphia’s population lives below the federal poverty level, and affordability remains a central consideration in all infrastructure decisions. PWD’s responsibilities compete for limited staff and funding, underscoring the need for a phased and accountable approach.

Continuous Improvement Initiatives

Adaptive management is a core tenet of PWD’s approach to utility management and was formally incorporated within the GCCW program as a tool to support potential program changes as needed.

PWD has continually used data collection, analysis and planning processes to evaluate progress, make program enhancements, identify risks and opportunities, and ensure the program is making progress as needed to meet obligations. PWD consistently seeks opportunities to integrate new tools and remains conscious of costs and program affordability.

To that end, PWD is evaluating a flood reduction project in the Germantown section of the City to potentially provide a substantial CSO reduction. This area of the City has experienced significant flooding impacts for years and will need large-scale infrastructure interventions to reduce flood impacts. PWD is undertaking a planning study to evaluate a deep conveyance and storage tunnel (Wingohocking Tunnel Planning Study) to mitigate flood risk in Germantown and surrounding neighborhoods and to significantly reduce combined sewer overflows to the Tacony-Frankford Creek. This project could serve as a model for future enhancements.

Safety and Public Use of Waterways

It is also important to note that Philadelphia’s rivers carry inherent safety risks — including strong currents, floating natural debris, submerged hazards, and commercial vessel traffic — independent of CSO activity. Public safety messaging reflects these broader conditions.

Looking Ahead

The Philadelphia Water Department remains deeply committed to cleaner waterways and continuous improvement. We are actively working with state and federal regulators, community groups, and advocates—including PennEnvironment—toward shared goals. Additional funding sources, policy support, and regional collaboration could help advance improvements even faster, without compromising affordability and the long-term health of our water systems. Philadelphia has already made substantial, measurable progress — and we are continuing to build on that success.