Operators of New York City’s publicly financed, privately run charter schools are bracing for changes promised by Mayor-elect Bill de Blasio — including the possibility of having to pay rent — that they worry could reverse 12 years of growth enjoyed under Mayor Michael Bloomberg.

De Blasio has pledged to charge rent to “well-resourced” charter schools and has called for a moratorium on allowing new charters to share buildings with traditional schools, taking aim at a Bloomberg policy that helped the schools grow from 17 to 183 during his time in office. The policy has also led to complaints that the charters draw an unfair amount of resources.

“It is insult to injury to give them free rent,” de Blasio said last summer, while campaigning for the Democratic nomination.

Charter school backers around the country are watching to see what happens in New York — which they consider an incubator for the charter school movement — while de Blasio supporters hope that the changes help fulfill his campaign promise to improve educational access for all children. De Blasio takes office on Jan. 1.

“The nation as a whole has always looked to New York City in this area,” said Nina Rees, president of the National Alliance for Public Charter Schools. “The climate in New York City is a healthy one because of the co-location arrangements.”

A majority of the nation’s charter schools either pay rent or are paying off a loan or bond issue for their buildings, according to Rees’ group, but New York City real estate pressures make that a challenge. She said that many charter schools wouldn’t have been able to open if they had to find their own building and start from scratch.

It’s unclear how much New York’s charters would pay. De Blasio has said he would use a sliding scale, with deep-pocketed charter operators forced to pay more, while some schools would continue to pay nothing. A spokeswoman said that de Blasio would work out the plan with his schools chancellor.

The city’s Independent Budget Office estimates that facility costs for the 40,000 charter school students in co-located buildings average $2,320 per pupil and that the city could raise $92 million if it charged rent. There are 114 charter schools co-located within traditional schools.

Critics note that more than a dozen New York City charter school executives are paid more than current New York City Schools Chancellor Dennis Walcott’s $212,614. Harlem Village Academies chief Deborah Kenny earns $499,146. Eva Moskowitz, a former City Council member and founder of Success Academies, earns $475,244.

Moskowitz has grown Success from one Harlem school in 2006 to 20 schools in several neighborhoods, with six more slated to open next fall. Its 6,700 pupils make it the city’s largest charter operator.

“We can’t afford it, and it would be taking dollars away from children and from their education to pay rent on a public school,” said Kerri Lyon, a spokeswoman for Success.

Moskowitz — who helped stage a march of more than 10,0000 people across the Brooklyn Bridge to protest de Blasio’s plans in October — has been singled out by de Blasio for criticism.

“There’s no way in hell Eva Moskowitz should get free rent, OK? ” de Blasio said at a forum in June. He told a United Federation of Teachers meeting last May that Moskowitz’s schools have “a destructive impact on the schools they’re going into.”

Schools that share space typically use separate entrances and have separate floors. Charter school detractors have complained that charter students get the best of everything, from playground equipment to bathrooms.

Ellen Darensbourg, a teacher at Public School 241, which shares a Harlem building with Harlem Success Academy 4 and another charter school, said that her school has been forced to move around the building numerous times over the last six years to give the charters more space.

Darensbourg said P.S. 241’s physical and occupational therapists have to work with special-needs kids in the hallway and the art teacher moves from room to room with a cart because the school no longer has a classroom — though the Success Academy school has an art classroom.

“It’s OK for their kids to have an art studio but it wasn’t necessary for our kids,” she said.

Lyon said that Success Academy generally enjoys a “pretty positive relationships with the schools that we share space with.”

Charter schools are run by private entities and have more freedom than traditional public schools to set their own hours and curriculum and pupils are chosen by lottery. Supporters say they give families an alternative to substandard public schools, while opponents point to studies that show mixed results.

New York City’s 70,000 charter school pupils represent about 6 percent of the city’s 1.1 million public school students.

Bill Phillips, president of the Northeast Charter Schools Network, said that charging rent and halting co-locations would slow the growth of charters to a trickle and deprive families of an option they want.

“These are public school kids,” Phillips said. “It is perfectly appropriate for them to be in public school space.”

(AP)