Frequently asked questions
What is it and where does it come from?
We all create sewage sludge. Anything flushed down the toilet or dumped down the drain in homes, schools, hospitals,
streets, businesses and industry flows through the sewer system to sewage treatment plants. Treatment plants clean the
liquid part of the sewage and attempt to remove some of the toxic metals, excess nutrients and pathogens from
wastewater. The resulting liquid is discharged into river, lakes and streams as effluent. The leftover solids and semi solids
that are “filtered” from wastewater make up the “sewage sludge.”
After “treatment” where does sewage sludge go?
Used water goes into New York City’s extensive
wastewater treatment system. This amazing network
system that cleans our wastewater consists of: over
6,000 miles of sewer pipes; 135,000 sewer catch basins;
over 494 permitted outfalls for the discharge of combined
sewer overflows (CSOs) and stormwater; 93 wastewater
pumping stations that transport it to 14 wastewater
treatment plants located throughout the five boroughs.
The New York City Department of Environmental
Protection (DEP), Bureau of Wastewater Treatment
(BWT) is responsible for the operation and maintenance
of all facilities related to the treatment of sewage. The
Bureau of Wastewater Treatment has 1,900 employees, an
annual operating budget of $262 million, and an annual
capital budget of $114 million. With these resources,
the 1.4 billion gallons of wastewater discharged by eight
million residents and workers in New York City each and
every day is processed at the treatment plants. After the
treatment process is completed, the plants release highquality, treated wastewater, called effluent, into the
waterways surrounding New York City.
How You Can Make a Difference?
Conserve water: There are many simple ways to use less
water every day, such as taking shorter showers, turning
off the faucet when you brush your teeth or shave and
fixing leaks.
Keep hazardous substance out of the sewer system:
Reduce the use of hazardous household products. Never
pour hazardous materials down a sink or toilet or dump
them into a storm drain. Save hazardous wastes for a
DOS household waste collection day or wrap them
safely in plastic and call the DOS for instructions. And
remember, it’s against the law to dump used motor oil
down a storm drain. It should be taken to a gasoline
service station for recycling.
Things you can do
DRAIN and SEWAGE TREATMENT Consulting
The New York City Department of Environmental Protection
The New York City Department of Environmental Protection distributes publications about wastewater treatment, the water supply system, water conservation and other environmental issues. For further information, or to obtain publications, or report water main breaks, streets leaks, open fire hydrants, sewer or storm drain backups and other problems, contact New York City’s 24-hour Citizen Service Center at 311. You may also visit the New York City DEP web site at: