Maryland’s attorney general and Department of the Environment are suing the District of Columbia’s water and sewer authority over a massive sewage spill that polluted the Potomac River earlier this year.

Attorney General Anthony Brown announced Monday that his office and the environment department had filed the complaint against DC Water, which owns the Potomac Interceptor sewer line, for failing to assess and institute improvements in their infrastructure.

A 72-inch section of the sewer line collapsed on Jan. 19, sending roughly 240 million gallons of untreated wastewater and “catastrophic” levels of pollutants into the Potomac River.

In a lawsuit filed in Montgomery County Circuit Court, Maryland officials accused DC Water, an independent authority of the District of Columbia, of negligence and violating state water pollution laws.

“DC Water knew this aging infrastructure was corroding, yet it delayed repairs and failed in its duty to protect this treasured waterway,” Brown said in a news release. “We are going to court to make sure they make it right for Marylanders.”

The U.S. Department of Justice filed a Clean Water Act complaint against the authority and the District of Columbia the same day Maryland announced its lawsuit.

The DOJ is seeking “financial penalties, sewer assessment and rehabilitation projects, and pollutant mitigation work to remedy DC Water’s failure to operate its sewer system in compliance with the Clean Water Act and its permits,” the department said in a news release.

DC Water officials said in a statement that they are “fully committed to the long-term rehabilitation of the Potomac Interceptor.”

“From the outset, DC Water’s highest priority was to safely and quickly contain the overflow and repair the damaged section of the Potomac Interceptor,” the authority said. “Crews implemented an emergency bypass system that successfully managed the majority of the overflow within five days and fully stopped all discharges to the Potomac River within 21 days. The repairs of the affected segment were completed in 55 days.”

DC Water said that it is working to rehabilitate more than 2,700 linear feet of pipeline in the area that were scheduled for improvement and that “initial remediation efforts are nearly complete.”

Ongoing testing of water quality is finding “downstream conditions have returned to normal and have remained stable for several months,” with low bacteria llevels near the site of the break, the authority says.

The state of Maryland is asking a judge to impose civil penalties of $10,000 per day for each violation and require DC Water to cover Potomac River cleanup costs, environmental testing and other damages. State officials note that the release occurred for more than eight days.

Last month, a New York firm sued DC Water on behalf of local property owners who claim they “incurred out-of-pocket costs, business interruption damages, property contamination, cleaning costs or other concrete economic losses.”

DC Water dates back to the 1850s, according to its website. The authority reports serving around 700,000 residents in the District and 1.8 million people in its surrounding suburbs, including Montgomery and Prince George’s counties, with wastewater collection and treatment.

The authority operates pumping stations, reservoirs, water storage tanks and flow-metering stations in the region. DC Water also operates more than 1,350 miles of pipes and 1,800 miles of sanitary and combined sewers.

The Potomac Interceptor was constructed in 1960 as a sanitary sewer to connect Washington Dulles International Airport to the D.C. sewer system. Though it’s a shared sewer system, Maryland Secretary of the Environment Serena McIlwain said in a news release that the Potomac River is Maryland’s and urged DC Water to restore it to health.

“The utility must take full responsibility for the damage caused and take immediate and lasting action to prevent future spills,” McIlwain said. “The river is part of our identity, our economy, and our way of life.”