The city is trying to hose homeowners by changing the water usage database — making it more difficult to challenge overcharges, according to landlords who are suing to stop the modification.

The city’s Department of Environmental Protection quietly made plans over the summer to switch the online public portal that tracks a property’s water consumption so that it only provides a one-year overview instead of a decade-long breakdown.

New York Water Management — an industry group representing thousands of property owners — sued earlier this month and won a temporary reprieve from the change that was supposed to happen on Sept. 13.

“The limitation on access to information will reduce challenges to overcharges and applications for credits thereby allowing NYC to collect more revenue,” the group says in the suit.

“It makes one wonder if the abandonment of the Department of Finance portal for the deficient MYDEP Portal is just a ruse to allow the City to collect millions of dollars to which it is not entitled,” it argues.

DEP Commissioner Vincent Sapienza said in a Sept. 9 letter to two City Council members that the new system is the result of a “major technological platform upgrade.” Sapienza added that he’d modified the system to allow people to search for five years of billing history in response to concerns by the real estate industry.

But opponents say that accommodation doesn’t go far enough.

“What happened to open, transparent government?” asked attorney Domenic Recchia Jr., a former city councilman who is representing the landlords.

“If Mike Bloomberg ever did this and Bill de Blasio was the public advocate, he would be screaming and rallying up everyone to say we have to go after the mayor. And now he’s the mayor.”

The current councilman, Justin Brannan (D-Brooklyn), said “residents should continue to have full access to their water bill records so we can be as open and transparent as possible.”

“I intend on introducing legislation if the city does not right this wrong,” Brannan said.

A city Law Department spokesman said, “This lawsuit has no merit and we’ll defend the agency’s decision in court.”

The parties are due in Brooklyn Supreme Court Wednesday.