TALLAHASSEE -- A legislative plan to give charter schools a cut of local school districts’ construction money would steer millions of additional dollars to large charter-school networks that are already sitting on tens of millions of dollars in cash, records show.

The charter-school industry is lobbying hard in the capital to gain a share of tax dollars raised by school districts to cover the construction and maintenance costs of traditional public schools — tax revenue that has dropped dramatically in recent years with plummeting real-estate values. Currently, school districts are not required to share these tax dollars with charter schools.

School districts say the proposal could cost them as much as $140 million a year statewide and cripple their ability to repair aging school buildings and pay debts for past construction. But charter school operators say the lesser funding for their students is inherently unfair, and argue that withholding construction money has stifled charter schools’ growth.

Earlier this month, Doug Rodriguez, the principal of the Doral Academy Preparatory Middle/High charter school, told a Senate committee that the lack of construction money has “placed a cap on our school. We’re not able to expand.”

But many charter schools, including Rodriguez’s, routinely collect more tax dollars than they spend, and sock away the unspent cash. The Doral Academy charter-school network, comprised of five Miami-Dade schools, had net assets of $13.6 million last year, much of it cash, records show.

The Doral Academy network is one of four large South Florida charter-school chains run by Academica, the state’s largest charter school operator. These four school networks — the Doral, Mater, Somerset and Pinecrest academies — had combined assets of more than $83 million last year, records show. This money is held by nonprofit companies that own the schools, which are managed by Academica, a for-profit company based in South Miami.

These schools could stand to gain millions more every year from the construction tax dollars, which would be distributed on a per-student basis. For example, the Doral, Mater, Somerset and Pinecrest academies — which now have 45 percent of all charter-school students in Miami-Dade County — would receive an additional $14.5 million from the Miami-Dade school district this year alone under the proposal.

Academica’s schools aren’t the only ones with growing reserves. The Keys Gate charter schools in Homestead, managed by Fort Lauderdale-based Charter Schools USA, have about $5 million in cash reserves, and the nearby Charter School at Waterstone, run by Charter School Associates, had $2.6 million in assets last year, most of it cash, records show.

Lynn Norman Teck, spokeswoman for the Florida Consortium of Public Charter Schools, said charters should not be cut out of construction funding because some schools have managed to save money.

“Their reserves are for a rainy day,” Teck said. “I don’t think it is fair to penalize a group of charter schools for being financially savvy.”

Andreina Figueroa, chairwoman of the Somerset Academy charter-school network, said her schools put money away to safeguard against funding cuts. The 31 Somerset schools in Miami-Dade and Broward have more than 10,000 students and $25 million in assets, records show.