The break occurred about 9 p.m. under the right lane of Nimitz fronting the Topa Financial Center, formerly the Amfac building. A river of water covered all four lanes, including portions of two that had lifted and sank.

Police detoured west-bound motorists to Alakea Street and blocked Queen Street heading to Nimitz. It was not known what caused the break or how long the repair work would take.

But Glenn Ah Yat, Honolulu Board of Water Supply lead pipe fitter, said that three of the four lanes might have to be closed during the repair work, which could last at least a day. Ah Yat, who was busy shutting off valves that led to the break, speculated that the age of the pipe contributed to the break.

No one could say for sure last night how many residents and businesses were affected by the break. Brian Grayling, who manages the 360-unit Harbor Square, said his nearly 2,000 tenants had no water last night.

"I've been managing high-rises for over 20 years and this is one of the worst cases I've seen. It just affects a very concentrated population," Grayling said. "If we have a fire, there's no water to put it out."

Gregory Rawlings, who lives on the top floor at Harbor Square, was inspecting the damage last night and took the lack of water in stride.

"We've already declared it a day off tomorrow. Since we can't take a bath we're just going to stay at home," Rawlings said. "We have about one gallon of water for spare, so it's going to be a short bath."