University of Delaware study IDs 2,000 century-old lead pipes in Wilmington

From Philly and the Pa. suburbs to South Jersey and Delaware, what would you like WHYY News to cover? Let us know!

Hidden beneath Wilmington’s streets for nearly a century, lead pipes have quietly carried water through thousands of homes. But thanks to a recent effort led by University of Delaware researchers and students, the city now has a clearer picture of how widespread the old pipes are, and what needs to happen next.

A team of environmental engineering students, working under Gerald Kauffman, director of the University of Delaware Water Resources Center, conducted careful research into historic city records.

“Out of the 70,000 [connections], the bottom line is working with the city’s consultant, the city’s Department of Public Works and the students, they found that 2,000 of the pipes of the 70,000 are lead,” Kauffman said.

The findings mark a crucial step in identifying and replacing hazardous pipes that could pose health risks to residents.

The unfortunate legacy of lead, why these pipes still exist

The use of lead in water pipes dates back to the late 19th century, when it was a preferred material due to its durability and flexibility.

“Going back to the first water pipes that were actually installed in Wilmington in the late 19th century before the turn of the 20th, many of the pipes were lead. That was a material that was easily molded, and little was known about the health effects,” he said.

Congress banned the use of lead pipes in new construction in 1986. But older cities — particularly in the Northeast — still have remnants of these outdated systems. Last year, the Biden administration issued new rules through the EPA that would require old lead pipes to be replaced.

Most modern homes and renovations now use safer materials like copper, while older neighborhoods remain at risk.

Exposure to lead in drinking water has been linked to serious health issues in a child’s development, including neurological damage. Kauffman pointed out examples like the Flint Michigan’s water crisis that underscored the dangers of lead contamination, making identification and replacement of these pipes a high priority.

How UD students helped map Wilmington’s lead problem

The project began when Wilmington’s Department of Public Works approached the University of Delaware Resources Center for assistance. Using decades-old, handwritten public records, students worked to identify where lead pipes were most likely located.

“The idea was to go through the maps that the city has, and we have GIS maps in our office in Newark, and go through all the repair books, the plumbers, the inspectors that the city would send out to work with the homeowners to fix the pipes,” Kauffman said, describing it as a tedious process. “This is physically pouring through these old, handwritten plumbing repair records, and cursive writing and abbreviations … some of these go back to 1926.”

The findings were significant — not just in scale, but in their impact on cost-saving efforts. Instead of the city having to dig up lawns and streets to locate lead pipes manually, the students’ work provided a targeted list of affected homes.

“My estimate is that the students saved the city about $15 million,” he said.