Montgomery County faces a $71 million -- or 5.2 percent -- budget hole next fiscal year, assuming no county employees get raises and county revenues see slight growth, the county Office of Management and Budget warned county department heads this week.

Several factors could increase the budget gap. For example, the projections do not account for storm cleanup or response, increases in the county's pension and health insurance costs -- both of which are expected to grow, according to county OMB Director Jennifer Hughes -- or changes to state or federal programs that would reduce county funding.

And the predictions assume no reductions in taxes, including the controversial energy tax that was extended beyond its expiration date this year.

The numbers assume there will be no wage increases for county employees.

Those workers have had their pay frozen for four years, though they received $2,000 one-time bonuses this year instead of raises. The Municipal and County Government Employees Organization hopes to change that, though, when they begin wage negotiations in November, said union President Gino Renne.

"Our priority is going to begin rebuilding our members' paychecks," said Renne. "We have an obligation and a responsibility to ... put them back on a path where they can begin growing their net income once again."

But county officials warn that this year will continue to be tight.

"This is not going to be a year where we're adding back in a lot of things," said Hughes.

Contributing to the deficit is the state's Maintenance of Effort law that requires the county to give Montgomery County Public Schools the same level of per-student funding each year. Since enrollment has been growing steadily by about 2,500 students a year, costs are expected to grow, too.

The county's budget projections take into account the growth anticipated in the schools. But if the schools request even more money than required by the state law, that could create a bigger budget hole. Schools Superintendent Joshua Starr plans to introduce his recommended budget on Dec. 11, according to MCPS spokesman Dana Tofig.

The $71 million gap is among the smallest the county has faced in recent years, noted County Council President Roger Berliner, D-Bethesda. The gap was nearly twice as large last year, and was roughly $300 million two years ago.

"We have always assumed that next year was going to be challenging," Berliner said.

Closing previous budget holes has required extensive cutbacks. Between fiscal 2009 and fiscal 2012, county libraries lost nearly 30 percent of their budget, the Department of Transportation lost 26 percent and the Department of Recreation was cut 23.5 percent. Some of these funds were restored this fiscal year, though not every all of them.