Combined Sewer Overflow

Most of Flushing Waterways is part of the NYC's combined sewer system, where the pipes that move our sewage are connected to the pipes that move our stormwater. When it rains, the combined system is overwhelmed by stormwater and combined sewer overflow (CSO) pipes discharge the excess sewage and polluted stormwater into our waterways without being treated at a wastewater treatment plant. The excess sewage and polluted stormwater includes waste from toilets, street litter, pet waste, and more!

Our sewer system is over 150 years old, which is a huge problem when NYC experiences any type of wet weather. In some parts of the City, between ¼ inch to 1 inch of rain an hour can trigger a CSO event. In Flushing Waterways, it takes only 1/10th of an inch of rain an hour to overwhelm the system where our treatment plants cannot handle the volume of waste it receives!

For more information on NYC's sewer system, check out SWIM Coalition and their advocacy for better stormwater infrastructure.​​

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The city's problem with CSO and insufficient stormwater management is a public health and access issue. CSOs contain disease-causing bacteria and pollution makes it dangerous to do anything in the water. This impacts water users (fishers, boaters, swimmers) and our watershed communities' sanitary conditions and quality of life. If left untreated, CSOs also have devastating effects on fish, wildlife, and aquatic habitats. 

New York City is required to ensure our waterways are fishable and swimmable. To do this, the NYC Department of Environmental Protection (DEP) creates long term control plans (LTCP) to address CSO. 


You can help by reporting illegal dumping from pipes that aren't CSO pipes to the Department of Environmental Conservation (DEC). Here are 3 ways to report: 1) email the DEC yourself, 2) reach out to Riverkeeper and they can help with filing the complaint, and 3) reach out to Guardians and we can help report the incident. 


Photo by Madeleine Pryor

How can you help?

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