“We cannot wait when we have an unusually high number of students in portables,” Montgomery County Executive Isiah Leggett, shown in April, said. (Jeffrey MacMillan)

County executives from Maryland’s three largest jurisdictions joined forces Tuesday to urge the General Assembly to provide more money for building and repairing public schools in their counties.

Montgomery County Executive Isiah Leggett, Prince George’s County Executive Rushern L. Baker III and Baltimore County Executive Kevin Kamenetz went to Annapolis on Tuesday to state their case for a partnership with the state, a deal that would allow them to borrow more money for school construction with the state’s help.

“This is truly a united effort,” Kamenetz said at a news conference. “For the first time in recent history, Baltimore County, Montgomery County and Prince George’s — or the ‘Big Three,’ as we often refer to our counties — are working together on an issue that is critical to each of our respective counties.”

The county executives, who represent school systems that educate 44 percent of the state’s public school students, described schools in their districts with portable classrooms, leaky roofs and inadequate bathrooms. For Maryland to continue its success in education, they said, the school construction needs in their counties must be met.

Leggett said it is imperative that state lawmakers consider a funding mechanism this legislative session to address Montgomery’s surging enrollment and aging school facilities.

“We cannot wait when we have an unusually high number of students in portables,” he said. “We need to respond to this challenge today. And I believe that when you look at the evidence, there is a compelling case in Montgomery, Prince George’s and Baltimore County, and really in many places throughout the state of Maryland.”

Last year, the General Assembly passed legislation that will enable Baltimore City to repair and reconstruct about 50 schools. Under that law, the city, the school system and the state will contribute a combined $60 million annually for the next several decades.

The county leaders would not offer any specifics about how much funding they are requesting from the state or how a partnership with the state might work.

“We’re here today to explain the challenge,” Leggett said. He said the executives would return to hammer out a plan, which would include greater flexibility in borrowing money.

Baker said the counties are not looking for a handout.

Prince George’s “is willing to put our money up there,” he said. “But we need the state to step up.”

Baker said repairing and building schools is a key component of his efforts to improve education in the county. “We need to not only provide quality teachers, quality workers and quality bus drivers, but also quality facilities for our students, and that’s what we’re asking today,” he said.

The county executives, all Democrats, were flanked by state lawmakers, but some of them said it was unlikely that additional funding would be obtained this year, given budget constraints.

“It’s going to be a heavy lift,” said Sen. Douglas J.J. Peters (D-Prince George’s). Peters said his county has about $300 million in financial obligations for the Purple Line light-rail project and a new county hospital. He said he is unsure how the county can come up with additional money if it partners with the state on a school construction plan.

Senate President Thomas V. Mike Miller Jr. (D-Calvert) suggested before the news conference that there was little chance the legislature would provide the kind of school construction package the county executives are seeking.

“I’m going to stand with them,” said Miller, whose district includes part of southern Prince George’s. “They’re my friends. . . . But they’ve got to be told the cold, hard facts of life.”

He pointed out that Baltimore has a much higher property tax rate than either Montgomery or Prince George’s counties and said the jurisdictions would probably “have to look inward” to fund additional school construction of the magnitude they are seeking.

John Wagner contributed to this report.