Mayor’s mouth runs dry

Mayor de Blasio was eager to ride to the rescue during last year’s lead crisis in Flint, Mich., but when it comes to tainted water in New York City public schools, he didn’t have much to say Monday.

Hizzoner repeatedly refused to answer questions from The Post about Monday’s frontpage story revealing that elevated lead levels were recently found in water from about one in every 20 elementary-school taps.

De Blasio and other officials rode the NYC Ferry boat Lunch Box to a Brooklyn news conference, where Deputy Mayor Alicia Glen broke a fake bottle of bubbly to christen the vessel, which doesn’t start operating until May 1.

The mayor gave a nearly nine-minute speech, then stepped away from the podium and ignored a question from The Post, with an aide approaching and insisting, “No, we’re not taking any questions. Thank you.”

De Blasio also refused to respond to a second question as he passed within earshot.

His silence was a marked contrast to his February 2016 reaction to the scandal over lead-tainted drinking water in Flint.

At that time, he and First Lady Chirlane McCray launched a “NYC Loves Flint” fund-raising effort through the Mayor’s Fund to Advance New York City.

“While we need to hold people accountable for the terrible decisions that led to this disaster, that cannot be the only focus of our outrage,” McCray said in a statement posted on the city’s official Web site.

“The people of Flint are counting on us to turn our anger into ACTION.”

McCray added: “Thanks to all of you, the people of Flint will receive some muchneeded support. They will also know that New York City has their back.”

The “NYC Loves Flint” effort directed donations to the United Way of Genesee County (Mich.) and the Community Foundation of Greater Flint.

Neither organization responded on Monday to inquiries about how much money de Blasio and McCray helped raise.