Open Sewer Atlas NYC

Pratt Center’s Josh Eichen and Pratt Institute graduate student Korin Tangtrakul have received funding from the Taconic Fellowship distributed by the Pratt Center for Community Development to create an open data source for NYC’s sewer system, called Open Sewer Atlas NYC. Follow the blog throughout the summer and fall of 2014 for regular updates on the project as well as posts de-mystifying the city’s sewer system. The final result will be static and interactive maps as well as open access to the shapefiles created throughout the project.


Where Does My Toilet Flush To?

Every day, nine million New Yorkers discharge 1.5 billion gallons of liquid waste into their sewer system. Underground and out of sight their urine, feces, and food scraps combine with litter and pollution from the street. This nasty brew then navigates 6,000 miles of pipe towards two possible futures: decontamination at one of 14 treatment plants or into our waterways untreated as Combined Sewer Overflow (CSO). The map below shows the drainage areas of the city’s 14 sewage treatment plants.


This is a HabitatMap. You can contribute to this map by CLICKING HERE and visiting the “Where Does My Toilet Flush To?” map on the HabitatMap website.

Where does my toilet flush to when it’s raining?

When it rains, the sewers become inundated by the runoff and the combined wastewater (polluted stormwater and sewage) is discharged into New York Harbor via a CSO outfall. CSO pollution can be triggered by as little as a tenth of an inch of rain, which essentially means that almost every time it rains, toilets are flushing directly into New York Harbor.

By clicking through the map above – thanks to! –  you can navigate the city’s waterfronts to find out where CSO outfalls are located near where you live or where you use access the water.

Are all CSO outfalls created equal?

No way. Some CSO outfalls discharge pollution very infrequently, or in small amounts.  Others overflow practically every time it rains, and are responsible for huge volumes of polluted wastewater entering the estuary. There are a handful – 15 out of the 434 CSO outfalls in the five boroughs – of CSO locations that are responsible for 50% of the total volume of CSO pollution that is released each year.  Have we mentioned that 27 billion gallons of CSO is released, on average, every year? In other words, 13.5 billion gallons of CSO pollution were released from the red dot locations on the map below.

But, not all of New York City is connected to CSO outfalls.  Nearly a third of the City has either a separate storm sewer system (rain off the street goes into its own pipes) or some other system (like the Staten Island Bluebelt).  To find out which area is connected to CSOs, click here.


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