Once again, top managers at the New York City Housing Authority will fail to make good on a promise made in federal court, this time to beat the rats. And again, it’s plain they failed from the start to take even basic steps to make compliance possible.

One tenant association reports that trash clogs garbage chutes as high as a building’s 14th floor, giving rodents a highway for invasion. Garbage rooms in multiple projects have become no-go zones. In one building, the room’s “been closed for a year . . . because employees are scared” of the rats.

Back in January, NYCHA agreed to 1) do a systemwide survey of its rodent nightmares, then 2) tackle those problems within 30 days.

Now the rat census is in: 71,394 units with at least two rat complaints in a year, but the agency’s 108 exterminators are a tenth of what it needs to tackle those jobs within a month.

In other words, even as the list of targeted units grew, no one moved to hire more exterminators or even look into borrowing some.

Turmoil at the top doesn’t help: NYCHA’s new CEO arrives only later this month, after two interim ones over the last year.

Still, when next the agency’s making legally binding vows, goals won’t be enough: It needs to admit to what it has to do, step by step, to have any chance of success.