A Fairfax County high school classroom.

Fairfax County is projecting a budget shortfall of as much as $85 million for fiscal 2017, adding to the pressure on county officials to cut spending while preserving services that have long made Virginia’s largest jurisdiction a draw for wealthy professionals and federal employees.

The budget gap in part reflects the ongoing effects of about $2.6 billion in federal spending cuts in the region since 2012 — cuts that have led to contractors laying off workers or shutting down.

The vacancy rate for office space in Fairfax has climbed to 16.5 percent, the highest since the early 1990s. Combined with a sputtering residential real estate market in parts of the county, officials say there is not enough property-tax revenue being generated to offset the increasing costs of county government.

“It used to be that this area was recession-proof,” County Executive Edward L. Long Jr. said Tuesday during a joint meeting of the County Board of Supervisors and county school officials. “That just isn’t the case anymore.”

The school system is facing a budget gap of $60.6 million for fiscal 2017, which begins in July. A task force seeking to cut as much as $75 million from the system’s $2.6 billion budget has recommended increasing class sizes and charging students and their families to participate in sports and to take Advance Placement and PSAT exams — charges that could amount to several hundred dollars per family per year.

“Sadly, the focus has been: What do we cut next?” School Superintendent Karen Garza said.

County officials are also preparing to begin talks in January geared at eliminating redundant government services and finding other unnecessary costs in Fairfax’s $3.8 billion operating budget.

Long said his budget projections factor in some extra costs the county is likely to incur. Among them: reforms to the police department recommended by an advisory commission formed in the aftermath of the fatal police shooting of an unarmed man in 2013. If fully implemented, the reforms — which include body cameras, new hiring and updated training — would cost about $6 million per year over the next five years, Long said.

Garza urged the Board of Supervisors to steer more money toward increasing costs faced by the school system — largely driven by an influx of low-income students in need of English-language instruction and other services.

She noted that the 3 percent increase in school funding being proposed by county officials wouldn’t even cover the $73 million that is needed to give Fairfax teachers the raises they are anticipating. “The fact is, we’re lagging in pretty much every area,” Garza said.

Sharon Bulova (D), chairman of the Board of Supervisors, said Fairfax plans to lead an effort to pressure the Virginia General Assembly to approve more funding for public schools. Since 2007, she said, Richmond has reduced education spending by $1 billion.

“It’s a frustrating situation,” she said. “And, that frustration is being reflected in this conversation.”