A skyline of Philadelphia
Philadelphia, the largest city on the Delaware River, contributes the lion's share of the river's dissolved oxygen problem. PHOTO BY MEG MCGUIRE

Population served by the Delaware River Basin jumps by 600,000
New census figures reveal that 14.2 million people are served by the basin

| February 17, 2023

The Delaware River Basin serves a population of 14.2 million people, up from 13.6 million based on population figures from the 2020 census.

The total population served is often quoted in various sources as being anywhere from 13 million to 15 million people, but 14.2 million is the new number, according to a presentation by Sara Sayed at the Delaware River Basin Commission’s Water Management Advisory Committee. 

The previous figure of 13.6 million was derived from 2016 census data.

2020 population served with Delaware River Basin waters


The graph above shows how the figure was derived but also offers a neat snapshot of what water from the river goes to where.

Most readers know that the New York City reservoirs at the headwaters of the Delaware River supply about half of New York City’s water needs. 

Within that 4.7 million people served are various local municipalities that take water from the New York City’s pipeline, such as Marlboro in Ulster County, N.Y., and the Town of Newburgh in Orange County, N.Y., where the water from the reservoirs crosses under the Hudson by way of the Delaware Aqueduct.

That, by the way, is the supply line that’s going to be closed later this year in order for New York City to repair a sizable leak. That work was postponed from last year.

There are, of course, residents of New York State who live in the watershed, and they’re counted in the 117,000 people at the top right of the graphic.

The water that goes to New York City is labeled on the map as a diversion, as are the 1.1 million people served in New Jersey via the Delaware and Raritan Canal. They are called diversions because they leave the watershed and empty into other water systems.

There’s another 2 million people who are served in New Jersey but the water stays in the watershed as it is recycled by dozens of wastewater treatment facilities and made safe to drink by a slew of drinking water distributors.

The largest user of Delaware River water is, not surprisingly, Pennsylvania, which has the largest land mass in the watershed. The watershed serves 5.8 million people. 

Delaware too, at 774,000 people, uses Delaware River water and recycles it back into the bay.

Lastly, look at the little blue box labeled Chester Water Authority. It imports water for 190,000 people from the Susquehanna Basin. 

Water transfers between basins has become a hot topic as the new rules for fracking wastewater have been passed by the Delaware River Basin Commission.

Meg McGuire

Meg McGuire

Meg McGuire has been a journalist for 30 years in New York and Connecticut. She started in weekly newspapers and moved to full-time work in dailies 25 years ago. She knows about the tectonic changes in journalism firsthand, having been part of what was euphemistically called a "reduction in force" six years ago. Now she's working to find new ways to "do" the news as an independent online publisher of news about the Delaware River, its watershed and its people.

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