A major water main break in downtown Minneapolis at mid-afternoon Thursday cut off or reduced water service to downtown and a major swath of the city.

Workers were not expected to finish repairs until well into the evening after isolating the break. Traffic and buses service were rerouted.

The break was probably caused when an unidentified excavation contractor working for a utility company was working near the pipe shortly after 2 p.m., according to Marie Asgian, the city’s superintendent of water distribution. The break occurred at Hennepin and 2nd St. N., where a grocery-apartment complex is under construction. Water surged through nearby streets, and several bus routes detoured.

Workers on the scene said that an excavation bucket ruptured the main. The main is one of several major pipes carrying water across downtown to distribute through the city and caused a major impact downtown, with reports of lower pressure extending beyond Abbott Northwestern Hospital and to Lake of the Isles and University of Minnesota .

“We’ll work into the night, whatever needs to be done,” Asgian said. “Nobody is going home until this is complete.” The city said a four-block area near the break will take longer to regain service. That area is S. 2nd St.

The loss of water forced some businesses to curtail service or close temporarily. At The Crossings condominium nearer the break, workers attached a hose to a fire hydrant so the hundreds of units in the building could regain water.

The kitchen closed at The Local restaurant at S. 10th St. and Nicollet Mall, leaving the staff serving beer and wine in disposable cups. General Manager Josh Petzel said happy hour will be affected and he’d already had numerous cancellations for dinner reservations. He said his staff was able to save enough water in buckets to continue washing their hands.

Asgian said the cast-iron pipe will be repaired by cutting it and placing a sleeve over the break. She said that will happen after the break is isolated. Typically those pipes rest eight feet below the surface.

At Hennepin County Medical Center in downtown Minneapolis, surgeries and other operations remained on as scheduled despite the water loss thanks to a back-up system, a spokeswoman said.

The Mill City Museum closed at mid-afternoon due to the break, and residents of nearby lofts were left with little or no water.