A 6-foot-deep sinkhole on 56th Street between Fifth and Sixth avenues caused by a broken water line was filled by the start of the afternoon rush hour yesterday, but it left only one lane open to vehicular traffic for most of the day and a local restaurant worrying about its clientele.

Early yesterday morning, a leak in a fire service line started weakening the ground. It caused the service line – which supplies tap water – to break, according to Charles Sturcken, a spokesman for the Department of Environmental Protection. The combination of the two leaks caused the street to cave in. Mr. Sturcken said the line was not owned by the city, but a DEP crew had to fix the sinkhole. “We stepped in, fixed the line, and we’re going to bill [the owner],” Mr. Sturcken said, estimating the cost at “tens of thousands of dollars.”

The emergency repairs left dozens of residents without water along one side of 56th Street, and Con Edison cut off steam service to prevent an explosion.

“Very cold water going onto hot steam pipe could cause a rupture,” Mr. Sturcken said of the precaution.

Robert Hamilton, manager of Beacon Restaurant on 56th Street, said he had seen clouds of steam billowing out of the street since Sunday. Even though Beacon did not lose water, Mr. Hamilton said the sinkhole still hurt business.

“It definitely created a pretty big diversion,” Mr. Hamilton said. “It probably deterred some guests that were either driving from out of town or that were looking to park near the restaurant. It was a pretty big mess.”