Two ruptures in an interior water main at the Federal Home Loan Bank Board Building last night sent thousands of gallons of water pouring through the nine-story structure, and officials were uncertain whether all offices of the bank board would be open today.

The incident occurred about 9 p.m. after D.C. firemen responding for a minor fire in an elevator electrical panel charged the water main. Fire officials said water system gaskets in the basement and on the seventh floor blew out under the pressure and loosed torrents of water throughout the L-shaped building at 17000 G St. NW.

Battalion Fire Chief Richard Hubscher said firemen would remain in the building at least until dawn pumping out water and to guard against electrical shorts. He said the coursing water ruined desks, filing cabinets and office furniture.

A basement computer room also was flooded, but it was unclear last night whether any equipment there was damaged.

There were no injuries in the fire, which was quickly extinguished, or as a result of the flooding, fire officials said. An estimate of damage was not immediately available.

Officials of the bank board, which regulates the nation's savings and loan industry, said it was likely that some portions of the building would be closed today. A determination would be made this morning, they said, and would depend largely on whether the building's elevators can be operated safely.

The Maison Blanche restaurant on the ground floor was not damaged and will be opened today as usual, its owner said.