Willis Elkins, a program manager for the Newtown Creek Alliance, at the creek in Queens. Every year billions of gallons of waste water are discharged into New York waterways when drainage is overloaded because of precipitation. Credit Kevin Hagen for The New York Times

New York City is calling on residents in parts of Brooklyn and Queens to cut back their water use during rainstorms by postponing showers and other chores — even waiting to flush toilets. The reason is that household sewage flows into the same underground sewer pipes that also collect rainwater runoff from rooftops and streets.

When those pipes are overloaded with rainwater, the combined overflow is then discharged directly into nearby rivers, bays and creeks instead of going to wastewater treatment plants.

The new “Wait …” campaign is the latest strategy by the city’s Department of Environmental Protection to reduce so-called “combined sewer overflows” that have long polluted local waterways, closed down beaches and plagued recreational sports. Today, about 20 billion gallons of combined sewer overflows are discharged annually into waterways, down from nearly 110 billion gallons in 1985, according to city officials. Typically, about 90 percent of that combined overflow is rainwater runoff.

By now, many New Yorkers are accustomed to doing their part for the environment by recycling trash, saying no to plastic shopping bags and using air conditioning sparingly on hot summer days. But even the most conscientious residents may not necessarily make the connection between the water that swirls down their drains during a rainstorm and the resulting sewer overflows that muck up the rivers where they sail or kayak.

Angela Licata, a deputy commissioner for the Department of Environmental Protection, said that in about 60 percent of the city’s sewer system, the same pipe is used to collect rainwater and sewage from homes and businesses, mainly in areas with older infrastructure. It was not until the 1950s that the city began building separate lines to avoid overloading the sewer system. “We’re grappling with this very difficult legacy problem,” she said.


The Newtown Creek Wastewater Treatment Plant in Brooklyn. A new program aims to get residents in parts of Brooklyn and Queens to cut back their water use during rainstorms to try to prevent the overloading of sewer pipes. Credit Kevin Hagen for The New York Times

The city has spent more than $45 billion since the 1980s to improve wastewater treatment and reduce the discharge of combined sewer overflows, resulting in waterways that are the cleanest in more than a century.

It has built and upgraded wastewater treatment plants, and is spending about $1.5 billion just on green projects such as installing “curbside rain gardens” and other infrastructure in parks, playgrounds and public housing projects to absorb storm water and keep it out of the sewer system. It also plans to disinfect some sewer overflows before they are discharged from sewer lines by using a chlorination process in the pipes.

In total, the city has 14 wastewater treatment plants that process an average of 1.3 billion gallons of sewage on rainless days. They can generally handle up to 3 billion gallons per day.

The new campaign aims to reduce the combined sewer overflows into Newtown Creek, a 3.5-mile-long waterway that forms part of the border between Brooklyn and Queens; and Bowery Bay, and Flushing Bay and Flushing Creek in northern Queens.

To sign up volunteers, the city will run ads on Facebook, partner with local environmental groups, and mail fliers to about 30,000 homes in two dozen neighborhoods that lie in the drainage areas for those waterways, including Williamsburg, Greenpoint, Astoria, Steinway, Jackson Heights, Elmhurst, and Corona. The campaign will focus on those living in single-family homes because their water usage data will be easier to collect and analyze, according to city officials who hope to eventually expand it to apartment buildings too.

One recruitment pitch compares the overflows to a familiar problem: “It’s like rush hour on the freeway: there’s only so much road and if everyone uses it at the same time, it can get jammed. And just like rush hour, the best thing to do is avoid it.”

City officials will monitor real-time rainfall data at the Newtown Creek and Bowery Bay treatment plants to determine when combined sewer overflows are likely. Once gauges at the plants register a half-inch of rainfall, volunteers will be sent a text message asking them to wait to use water. After the storm ends, and plant operations return to normal, they will receive a second text thanking them.


Mr. Elkins at a “combined sewer overflow” site at the English Creek, a tributary of the Newtown Creek, in Brooklyn. Credit Kevin Hagen for The New York Times

The new campaign has cost about $120,000 to develop and put into effect.

It grew out of an earlier effort by the Newtown Creek Alliance, which enlisted several dozen residents to curtail water use during rainstorms in 2014. Two years later, officials expanded upon that idea for a six-month pilot project in neighborhoods around Newtown Creek, enlisting 379 volunteers from more than 200 buildings. Of those, only nine quit the program, mostly because they were moving away from the area.

During the pilot project, volunteers were asked to wait a total of 13 times — with the average wait lasting a little over seven hours. By the end, there was a 5 percent drop in the average daily water consumption in the buildings where the volunteers lived.

Sarah Lilley, 52, a freelance public radio producer in Williamsburg, did not find it hard to give up water at certain times. She postponed showers and kept toilet flushing to a minimum. “You’re just talking about a rainstorm, you’re not talking about a weeklong blizzard,” she said.

Ms. Lilley became so well trained that she continued to do those things on her own after the pilot project ended. “I’m the one who knows that I could have had the sink running for 45 minutes after that dinner party and I didn’t,” she said. “I know the amount of water I did not use — and I can envision it not flowing down the street, and not picking up trash as it goes.”

Another volunteer, Sarah Balistreri, 38, a school curriculum specialist who lives in Greenpoint, said she sometimes had to shower before going to work, but she made it quick. And she washed laundry if it was her only block of time to get it done for the week. “I felt bad,” she said. “I wasn’t a perfect participant.”

But those were the exceptions. “My behavior over all has changed,” said Ms. Balistreri, who kayaks on Newtown Creek and has enjoyed the benefits of cleaner water firsthand.

To make sure she never missed a text, she even programmed the number into her cellphone along with an image of a poop emoji. It’s still on her phone.

“It’s a reminder,’’ she said, “of what this is all about.”