Yonkers’ School 5 opened in 1884, the year when “The Adventures of Huckleberry Finn” was first published and the cornerstone was laid for the Statue of Liberty.

It’s no wonder then that a standpipe burst inside School 5 in December, causing damage to nine classrooms and plenty more. School 5 is really, really old. In fact, at 133 years of age, it is the senior school building among Yonkers’ 39 public schools — one of the oldest school fleets in the country, with an average age of 75.

School 5 reopened recently after the city spent $2.3 million on emergency repairs. Students and staff were oddly thrilled to see fresh paint and bright lights in the hallways, uncommon amenities in the broken down Yonkers schools. It’s sad that it takes water damage to produce a decent learning environment at an elementary school in mostly affluent Westchester County.

Pretty much the entire public-education establishment in New York State knows that the public school buildings of Yonkers are in absolute disrepair — and have been for many years. There is a clear consensus that the schools are long overdue for major renovations. The situation is becoming desperate because student enrollment keeps growing, and the schools are already 4,500 kids over capacity. That’s almost as many students attend the entire Port Chester School District.

And yet, it remains unclear whether Gov. Cuomo or state Senate leaders grasp the urgency of the problem. Fixing the Yonkers schools, home to over 27,000 students, is all about money. A lot of money. But, as of now, it’s a mystery whether there is political will in Albany to figure out how to get the job done.

The numbers can make you wince: It’s expected to cost $2 billion to rebuild the Yonkers schools, in four phases over about a decade. Phase I would cost about $523 million, and would include the building of a new Gorton High School and two new schools. That’s what happens when you let repairs go for years and years.

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The state has already paid nearly the entire costs of rebuilding the schools of Buffalo, Rochester and Syracuse. But those cities were entitled to over 95 percent reimbursement because their property values are low. Yonkers is only eligible for about 70 percent reimbursement — and that is the problem. The city can’t possibly pick up 30 percent of the tab or $600 million. As Mayor Mike Spano likes to say as part of his lobbying pitches, a 1 percent increase in the city’s tax rate raises $3.3 million.

Yonkers officials are asking Cuomo and legislative leaders to either adjust the reimbursement formula or to provide a separate stream of cash specifically to fund the project. State legislators representing Yonkers are all on board and working to craft a political solution.

We know that Albany is aware that the Yonkers school buildings are a problem. Last year, after Spano led a major lobbying effort to #RebuildYonkersSchools, a bill was passed creating a new board to oversee the rebuilding project. The Yonkers Joint Schools Construction Board will soon be in place — but will it have enough money to carry out the project?

Cuomo, legislative leaders and Yonkers officials need to make real, concrete progress during the current legislative session on creating a financing plan. The small step taken with the creation of a construction board can’t be allowed to wither. That’s why Yonkers’ students are using a new hashtag: #Fund2Rebuild.

Of course, Yonkers always has its drama. The school system has needed several state bailouts in recent years to cover budget deficits. Now Superintendent Edwin Quezada says the system may face a $30 million shortfall in 2017-18, even without adding programs or staff. Any need for further state assistance could easily be used as an excuse to avoid facing the $2 billion project that must get done.

We get that Albany has a lot on its plate. And that $2 billion is a lot of money. But the Yonkers schools are deteriorating by the day. More and more kids are stuffed into basements and storage rooms. Planning such a massive project will itself be a major undertaking. The waiting must end in 2017.