An ambitious Washington County construction project intended to cut soaring energy costs and eliminate harmful wastewater runoff will begin in May in Stillwater Township.

The $19.7 million undertaking will reconstruct the county’s largest public works operation — known as the North Shop — to correct structural deficiencies that have caused fires, electrical hazards and mold.

“It’s in rough shape, to say the least,” said Commissioner Karla Bigham, who saw problems firsthand when she took a recent tour.

Don Theisen, who heads the public works division, said a new North Shop will address modern needs of a county that’s nearing a quarter million residents. The existing complex, opened in 1962 and modified in 1972, was built for a much less-populated county that didn’t require as many services, he said.

The new complex will open in November 2016. The 80 or so county employees assigned to the North Shop — including mechanics, drivers, engineers and the parks staff — will deploy to temporary quarters elsewhere during construction.

Improvements will include more space for maintenance of the county’s snowplows, warm storage for Sheriff’s Office vehicles, a fiber optic connection, rooftop energy-saving features, more restrooms for women and a wastewater disposal system that prevents runoff from washed trucks into nearby wetlands.

“This construction will allow us to address environmental concerns we have with the existing facility,” said Commissioner Fran Miron. “We’re going to create a much safer work environment.”

The county will fund the project with proceeds from $17.5 million in tax-exempt bonds issued this year, and $2.2 million in state aid funding.

Some members of the County Board had expressed concern in recent months about potential cost overruns with the reconstruction, but the budget Theisen presented to commissioners last week tightened those costs.

The final recommendation came $1.1 million under the engineers’ estimate, he told commissioners, who voted 5-0 to move ahead with the reconstruction.

Eighty-nine bids were received in 26 separate bid divisions, Theisen said.