Montgomery County Executive Isiah Leggett (D) on Friday issued a rare line-item veto of a portion of the storm water management program budget the county council had approved, saying lawmakers overstepped their authority by rejecting Leggett’s plan to restructure the program.

The veto was Leggett’s first in his nearly 12 years in office and the first in the county in a quarter-century.

In his veto memo, Leggett wrote that the council’s action “hurts our environmental efforts. It prevents needed changes. It ensures that County taxpayers will pay more and more in storm water management fees — and get less and less in return.”

Instead of the current model of multiple contracts for designing, building and maintaining storm water projects, overseen by the county’s Department of Environmental Protection, Leggett had proposed spending $48.3 million on a contract that would consolidate all three aspects. The contract would still be overseen by the department.

The council rejected the proposal 6 to 3 last month. Council member Tom Hucker (D-District 5) put forward an alternative plan that would continue the current contracting method. That passed 5 to 4.

The alternative plan went into the 2019 capital budget, which the council approved 8-1 on May 24. Council member Nancy Floreen (D-At Large) cast the opposing vote against that budget over the storm water issue, saying at the time that the council had made an “unwise decision.”

Council member George L. Leventhal (D-At Large) agreed with Floreen, saying at the meeting that Leggett’s proposal had fallen victim to lobbying by mid-level county environmental employees and environmental groups, which had opposed the change.

Josh Tulkin, state director of the Maryland Sierra Club, said his group was one of many urging council members to “hit pause” on Leggett’s proposal, and said they plan to urge a veto override, which would take a supermajority of six council members.

If there is no override, that portion of the storm water management program disappears from the budget.

Council president Hans Riemer (D-At Large) said Friday that he was not aware of any changes in the council that would lead to a supermajority.

“The executive is trying to make a profound change in how we do the work and a lot of council members have real questions about that and so it’s something that really needs to be vetted through a very significant legislative process,” said Riemer, who had voted against Leggett’s proposal.

Leggett spokesman Patrick Lacefield said the county executive plans to send the council a capital budget amendment after the fiscal year begins next month that would fund his proposal. That amendment would need a supermajority of the council to pass.