Hempstead Town is suing the Navy, Northrop Grumman, operators of a former dry cleaner and others in federal court for a minimum of $50 million over groundwater contamination that forced the closure of water wells in Levittown.

America’s most populous town filed the lawsuit June 30 in U.S. District Court in Central Islip, claiming that negligent and reckless behavior and lack of proper controls contaminated drinking water supplies in the town-run Levittown water district, which serves 50,000 customers.

The town discovered low levels of the chemical Freon and volatile organic chemicals, including the degreaser and possible carcinogen trichloroethylene, or TCE, at two well sites in July 2013.

The wells — one at Wantagh Avenue and Entry Lane and another spot 1,200 feet to the west — were cut off from the system and the town is spending an estimated $7 million to build treatment facilities to remove the contaminants. One system is up and running, the second will be operational before the end of the year.

In a statement Hempstead Supervisor Anthony J. Santino said the lawsuit was an attempt to protect residents of the water district and to recover money spent on remediation. “The Navy and its contractors are responsible to remediate their contamination,” Santino said. “The burden — and price tag — for corrective action should not fall on taxpayers.”

Sen. Chuck Schumer (D-NY) said water district rate payers should not have to pay for a mess not of their making. “Our water districts must be reimbursed for these growing costs,” he said in a statement.

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The lawsuit calls into question the accuracy of groundwater flow models and focuses on sites in Bethpage, Hicksville and Levittown where contamination was released and mixed together, flowing into the drinking water supply area for Levittown, court documents show.

Some of the contamination at issue stems from a more than 600-acre parcel in Bethpage, where the Navy and what is now Northrop Grumman manufactured, tested and developed airplanes and space equipment from the 1940s until 1998. A complex series of underground plumes are part of several cleanup plans under supervision by the state Department of Environmental Conservation.

A nearby former plastics and latex manufacturer in Hicksville on New South Road known as the Hooker/Ruco site is named in the suit. Three other companies associated with the site through ownership or previous names — Bayer MaterialScience, Covestro and Occidental — are also listed.

A former dry cleaner on Hempstead Turnpike in Levittown called American Drive-In is part of the suit, as are four individuals who owned or managed the property and an associated trust.

The Navy declined to comment because of the litigation. Northrop Grumman and Covestro did not respond to requests for comment.

Manhattan environmental attorney Lawrence Schnapf said the town’s lawsuit was not unusual for Long Island and that “multiple parties can be jointly liable if they contributed to the same harm.”

He said the town would have to show that Navy, Grumman and the others named used the kind of chemicals that mixed together and were now found in the drinking well supply.

“Other water districts have filed similar lawsuits against multiple defendants . . . ,” he said.

Bethpage water district levied a similar suit against Navy and Northrup Grumman in 2013 but it was mostly thrown out by a judge who said discovery of contamination was not within the three-year statute of limitations.

In the Hempstead case, contamination was found in July 2013 and the suit filed last month.

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Before filing, Hempstead asked Navy and Northrop Grumman to pay for the design, construction and operation of treatment systems. According to the lawsuit, the Navy refused, saying a groundwater flow model had not predicted that contamination would reach the Levittown wells within 30 years.

But a later study of the flow model by United States Geological Survey concluded the modeling was incomplete, according to the 2011 report mentioned in the suit.

“Based on inaccurate groundwater flow data the Navy and Northrop Grumman have failed and refused to remediate contaminated groundwater impacting [Hempstead’s] wells,” the lawsuit says.