NEWBURGH, N.Y. — They scrutinized the paint on the walls, the lacquer on the woodwork and even the dirt that Karisma and Damian DePauw trekked into their home, an apartment in a century-old building along the western bank of the Hudson River.

But officials at the county health department struggled to explain why the couple’s young daughter had a high level of lead in her blood. That’s when her parents suspected the water.

“There’s no other explanation,” said Karisma, who worked as a nursing assistant before giving birth in 2018 — the year this mostly Hispanic and African American city was warned that its water contained unacceptable amounts of the toxic metal.

Lead pipes have long delivered drinking water to older municipalities in the Northeast and Midwest, along with the risk that they could leach lead. The water-contamination debacle in Flint, Mich., one of the nation’s worst public health disasters, highlighted the threat after thousands of children were exposed. Now, half a dozen years later, President Biden has put a sweeping remedy at the center of his plans to rebuild the nation’s infrastructure and address the legacy of environmental racism in minority and low-income communities.

The Biden administration wants to spend $45 billion via grants and low-interest loans to replace more than 6 million lead-pipe service lines across the country. The measure is one of the most popular parts of his $2.3 trillion infrastructure proposal — a CBS News poll showed 85 percent approval — and may help overcome Republican lawmakers’ resistance to the package.

These pipes are “a clear and present danger to our children’s health,” Biden told Congress last month, drawing one of the biggest applause responses of his address.

The Natural Resources Defense Council estimates that from 2018 to 2020, more than 61 million people were served by water systems with lead levels exceeding the 5 parts per billion threshold that the Food and Drug Administration sets for bottled water. Yet replacing lead pipes has proved to be a costly and difficult endeavor for many of the cash-strapped cities where they are common. Milwaukee’s current rate of replacement would take about 70 years for completion. In Chicago, which has about 380,000 lead lines, the job as recently proposed would take 500 years.

In Newburgh, a historic, once-prosperous center of manufacturing and shipbuilding, help from the federal government cannot come soon enough. A quarter of the city’s 28,000 residents live in poverty, many in tired brick rowhouses built generations before a 1986 nationwide ban on installing lead pipes.

“Send me the money,” Wayne Vradenburgh, head of the local water department, quipped in late April. “Send me the check.”

The latest lead problems here began in 2016, when Newburgh stopped pumping water from Washington Lake after environmental officials detected perfluorochemicals. The pollutants, which research has linked to cancers and thyroid and liver problems, had been used in a firefighting foam on a nearby Air National Guard base.

Almost immediately, local officials switched to the Catskill Aqueduct. That’s the celebrated source of drinking water for New York City to the south, but in Newburgh, the slightly more acidic chemistry of water from the Catskill Mountains accelerated the breakdown of aging lead pipes.

Lead levels spiked above the Environmental Protection Agency’s “action” level of 15 parts per billion. In response, caustic soda was injected into the water to slow corrosion and bring lead levels down. And to help halt future leaching, the city got $749,000 in state funding to replace 95 lead service lines, tearing up streets and front lawns to reach the old pipes and install new ones made of copper.

For Lester Ortega, a construction worker who lives a few blocks off Broadway, the city’s main commercial strip, the program meant he didn’t have to spend nearly $10,000 to unearth the lead line supplying water to his house.

The father of three was grateful for the aid and relieved when the job was finished. “I’ve read a lot about what lead can do to your body,” he said.

The community’s need is far greater, though; Newburgh quickly ran out of money supporting such efforts. Vradenburgh said he was told “we were getting another allotment of $500,000 before the pandemic, but that never came about.”

“I have a list, as we speak, of customers that are waiting to get their line replaced,” said Vradenburgh, who estimates that around 2,900 lead service pipes remain underground. His staff is trying to get a more accurate number. But with an annual department budget of just $3.8 million, he said he needs more grant money just to complete the count.

One ready customer is Gabrielle Burton Hill. She suspects the line to her family’s longtime home is made of lead. During the late 1990s, another period when Newburgh’s water exceeded federal lead limits, her infant daughter was hospitalized for a week due to lead poisoning, she said.

Given that frightening experience, she buys three or four cases of bottled water a week to avoid drinking out of the tap. So do many others. The bodegas along Broadway put jugs of bottled water for sale right in front.

“I don’t think anyone really has trusted our water in quite a few decades,” said Burton Hill, a former fast-food manager turned activist.

She was among more than a dozen residents who helped form the Newburgh Clean Water Project, a nonprofit advocacy group that joined the Sierra Club, NAACP and other major environmental and civil rights organizations in suing the EPA. Their target is lead regulations put in place in the waning days of the Trump administration.

The old rule, written in 1991 under President George H.W. Bush, required 90 percent of homes tested to have lead levels below 15 parts per billion. The Trump administration’s rule set a tighter “trigger level” of 10 parts per billion, but the change still left millions of Americans at risk of tainted tap water even when a water utility is in compliance. Young children are most vulnerable to lead poisoning and can suffer irreversible brain damage.

“We had hoped for a real overhaul,” said Suzanne Novak, a staff attorney at Earthjustice who is leading the litigation while the EPA reviews the rule for a potential revision. “It’s been 30 years.”

While the Trump administration did close several loopholes — utilities now must take all water samples from homes with lead service lines, if possible — it weakened one crucial element. Rather than require utilities exceeding federal limits to replace all lead pipes within about 14 years, the new deadline gives them 33 years.

“This is not rocket science to fix,” said Erik Olson of the Natural Resources Defense Council, which has its own lawsuit against the new lead rule. “You basically just need a backhoe.”

In Congress, improving water infrastructure has bipartisan support. The Senate just voted 89 to 2 to pump $35 billion over five years into cleaning up the nation’s drinking and wastewater systems. Still, that’s far short of the $111 billion Biden is calling for to remedy service lines and treatment plants.

The president considers his initiative a key economic driver as well as the right move for public health and environmental justice. Tearing out the problematic pipes will “create thousands and thousands of good-paying jobs” for plumbers and pipe fitters, he told Congress.

As it waits for the money from Washington, the Newburgh water department is trying to rebuild confidence in the system.

“You can’t put a money value to that,” Vradenburgh said. “We lost the trust of the public.”

He continues to offer residents monthly tours of the city’s water-treatment plant and the multimillion-dollar filtration system officials approved after switching their supply source to the Catskill Aqueduct. Standing between two of 18 towering purification tanks, Vradenburgh bragged that his department was sending out “the best water in the state.”

Yet the public relations effort is tough going. The department recently raised rates by 15 percent to help cover the cost of the filtration project as well as hefty lawyer fees for the city’s lawsuit against the military over the contamination of Washington Lake.

“We shouldn’t have to pay for this water,” said Cindy Chesser, an accountant whose home had lead levels spike to a staggering 297 parts per billion in early 2019. “We can’t even drink it.”

The DePauws are just grateful their daughter’s lead levels have declined after a diet of lead-absorbing broccoli and peanut butter. The couple moved to a new apartment in Newburgh so quickly after their daughter’s diagnosis they didn’t have the chance to analyze the water before they left. But they made sure the water at their new place tested clean.

Though the effects of lead poisoning can take years to emerge, Karisma said 3-year-old Aurora “is flying through every test that the doctor gives her.”

“Hopefully,” her husband added, “people can avoid going through the nightmare that we went through.”