Construction of Wolf Trap Fire Station 42 is nearing completion, but budget constraints will probably prevent the station from being staffed until 2015. (Shamus Ian Fatzinger/FAIRFAX COUNTY TIMES)

The new Wolf Trap Fire Station on Route 7 looks as if it’s nearly ready to begin dispatching ambulances and firetrucks.

But because of the county’s tight budget picture for fiscal 2014, Station 42 probably will not be staffed for emergency operations until January 2015 — about a year later than originally planned.

“It was just a calculated decision that had to be made to balance the budget,” Deputy County Executive David Rohrer said.

Opening the new station will cost about $4.2 million, including equipment and 29 additional staff positions, Rohrer said. Most of the large equipment has been purchased and is being used at other stations, he said.

In consultation with the fire chief, Rohrer and County Executive Edward L. Long Jr. decided that the station doesn’t have to open immediately.

The area that the Wolf Trap station will serve is covered by three other stations: North Point Fire Station 39 in Reston, Great Falls Fire Station 12 and Tysons Corner Station 29 on Spring Hill Road.

Those stations can meet current needs, but after the Silver Line opens at the end of this year and Tysons Corner begins redeveloping, the demands on the already busy Tysons Corner station are expected to increase, Rohrer said.

The slow economic recovery also has held back some of the expected growth in the area Wolf Trap will serve, buying the county some time, he said.

“We recognize that the need is coming,” he said. The Tysons Corner station “is a busy station. Wolf Trap will take some of the load off of them going forward.”

The Wolf Trap station is intended to house an additional water tanker and other equipment needed to fight fires in the portions of Great Falls that are not served by municipal water and, therefore, do not have fire hydrants.

Currently, a tanker positioned at the North Point station provides coverage.

Supervisor John Foust (D-Dranesville) said he does not intend to ask for a budget amendment to begin service at Wolf Trap earlier. With no additional money available, starting service now would mean cuts elsewhere in the budget, he said.

“I am not happy with the idea, but I understand the restraints we are working under,” he said.

The building will not sit empty while it awaits staffing, Rohrer said. The Fire and Rescue Department intends to use the space for classroom training for personnel on that side of the county, keeping them closer to their base stations than if they had to go to the training academy on West Ox Road in Fairfax.

The plan for staffing the new fire station will not be official until the Board of Supervisors approves the budget in the spring.

For the first time, the county is working on a two-year budget that demonstrates how fiscal 2014 spending levels will affect fiscal 2015. The final spending plan for fiscal 2015, which is anticipated to include staffing for the Wolf Trap Fire Station, won’t be adopted until next year.