PWD Combined Sewer Overflow Program

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The Combined Sewer Overflow (CSO) Long Term Control Plan Update (LTCPU)

Philadelphia’s Combined Sewer Overflow Long Term Control Plan Update seeks to achieve the regulatory requirements of the National CSO Control Policy through a comprehensive watershed-based approach. The Long Term Control Planning Guidance set forth by the U.S. EPA supports the implementation of a comprehensive watershed management approach and recognizes that the major advantage in using such an approach is that it identifies multiple solutions that are cost effective measures which result in site specific improvements to problems caused by the impacts of CSO and non-CSO sources of pollution on water quality.

History of Combined Sewer Overflows in Philadelphia
During the course of Philadelphia’s development in the 19th and 20th centuries, the majority of the city’s streams were diverted into pipes--their valleys leveled with millions of yards of fill and overlaid with a grid of streets. These pipes were designed as combined sewers, carrying the stream flow, raw sewage and stormwater runoff. Read More ...

What are Combined Sewer Overflows?

A combined sewer system is a wastewater collection system owned by a municipality which transports wastewater from homes, businesses and industry, and stormwater from storm drains on our city streets and property roof leaders through a single-pipe system to a Water Pollution Control Plant. Read More ...

System Overview

Below ground lies a vast network of underground pipes. In Philadelphia, we have a sewer system that is 3,000 miles long. That’s enough to stretch from the east to the west coast of the United States.

Philadelphia, like many older cities across the country, has some areas with a combined sewer system and some areas with a separate sewer system. Read More ...

A Successful CSO Program – The Balanced “Land-Water Infrastructure” Approach

The Philadelphia Water Department is committed to a balanced “land-water-infrastructure” approach to achieve its watershed management and CSO control goals. Read More ...