When Mayor Eric Adams of New York declared that he would shut off water service to nonpaying customers, he cast the effort as a fight against big landlords bilking city taxpayers.

The biggest “delinquent” customer of all, however, went unnamed: New York State, according to an internal city list of the top 20 water delinquents obtained by The New York Times.

The top three nonpaying customers on that list are the state-controlled Metropolitan Transportation Authority; Riverbank State Park, on Manhattan’s West Side; and the Port Authority of New York and New Jersey, a bistate agency that manages the region’s ports and airports. Together, they owe a cumulative $76.5 million in overdue payments, according to the city’s calculations.

In all, New York City is owed roughly $1 billion in delinquent water and wastewater payments as of April. According to the city’s calculations, the M.T.A., Port Authority and Riverbank account for nearly 8 percent of that total.

The accused contest their deadbeat status for a variety of reasons. Many of the facilities run by the M.T.A. and the Port Authority do not have water meters, fueling disputes over exactly how much water has been used.

The state parks department and the city disagree over who is responsible for payments at Riverbank State Park, a 28-acre greensward with sprinklers, playgrounds, an Olympic-size indoor pool, an outdoor lap pool, a wading pool and also a city water treatment plant. (On Tuesday, Gov. Kathy Hochul appeared at the park to announce that she was waiving swimming pool fees at state parks this summer.)