Campaigns & Cases > Stop Polluters > Sewage Contamination > Combined Sewage Overflows (CSOs)

Combined Sewage Overflows (CSOs)

More than 27 billion gallons of raw sewage and polluted stormwater discharge out of 460 combined sewage overflows (“CSOs”) into New York Harbor alone each year. Although water quality in New York Harbor and throughout the Hudson River Estuary has improved significantly over the last few decades, many parts of the waterfront and its beaches are still unsafe for recreation after it rains. As little as one-twentieth of an inch of rain can overload the system. The main culprit is outmoded sewer systems, which combines sewage from buildings with dirty stormwater from streets.

This extraordinary degree of pollution imposes steep environmental, human health, and economic costs. CSO discharges, in addition to preventing safe recreation, impair navigation and damage fish habitat.

Fact Sheet – Storm Water CSO’s and Green Infrastructure

  • How and Why Do CSOs Occur?

  • What's In CSOs?

  • How Often do CSOs Occur?

  • YOUR LETTERS ARE NEEDED!Solutions To The CSO Problem

  • CSO Locations on the Hudson

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