With generators humming outside and chemical fumigation inside, the Prince George’s County administration headquarters swarmed with activity Monday, five days after a pond spilled its banks and deposited mud, fish, frogs and two feet of water in the six-story building.

After last week’s torrential rains, county employees on the building’s upper floors were told to work from home or report to other county buildings. But the unlucky workers whose offices were on the ground floor were called to Upper Marlboro on Monday to gather what they could to take to temporary office space in other government buildings in the county.

Late Monday, county officials announced that the headquarters building would be open to most of its 480 employees on Tuesday, except for those who work on the ground floor, where repairs continue. The County Council will stick with its plan to hold its Tuesday session at a facility in Riverdale.

“We are hoping to get it open as soon as possible,” said Brad Seamon, the county’s deputy chief administrative officer. The most damage — cost unknown — was to the ground floor, which houses land records, the marriage license bureau, the community relations office and a small cafeteria. There, workers had already removed soaked carpets, ruined computers and mounds of paper.

Pepco workers restored power to upper floors, and phones and computers on levels 1 to 5 appeared to be working Monday, but there were still problems with air conditioning and elevator service throughout the building.

The cost of the cleanup and losses to the county will be “in the millions,” Seamon said. The county has insurance for a portion of the damage caused by last week’s massive flooding, and also expects to get state and federal disaster aid.

Meanwhile, fumigation on the ground floor targeted mold, which might have grown during the flood. “We have not checked for mold, but you can assume there was some. Things were wet down there for a couple of days,” Seamon said.

Among the offices being relocated is the Community Relations office headed by Adam Ortiz. Ortiz and his staff were moving to a county building on Basil Court in Largo; other offices, such as the marriage license bureau, are being moved to the county courthouse near the administration building.

Word of the relocations did not reach everyone who had planned nuptials Monday. One couple showed up, only to learn that the office was closed.

Clutching a marriage license, the bride-to-be, dressed in a shimmering, off-white full-length gown, did not want her name used or her photo taken. She and the groom were trying to figure out whether they could go to another county, get another license and get married.