OAKDALE, Minn.-The water main that broke Sunday morning in the eastern Twin Cities suburb of Oakdale and forced the closure of part of Interstate 694 has been replaced and only one resident remains without water, city officials said Wednesday.

About 87,000 cars use that stretch of I-694 each day.

An 11-foot-long crack in the pipe resulted in a leak of more than 1.5 million gallons of water and created a massive washout or sinkhole that is expected to keep I-694 between Minnesota 36 and Interstate 94 closed until at least the weekend.

Shawn Nelson, utilities superintendent, said crews were backfilling the site on Wednesday and that the city's repairs were on track to be completed by Friday.

"We actually are ahead of schedule on our end," he said during a news conference at Oakdale City Hall.

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The city and the Minnesota Department of Transportation are coordinating efforts to repair the freeway.

"It could be (open) as early as this weekend," said Kevin Gutknecht, a MnDOT spokesman.

Nelson said he was "floored" when he saw the crack in the 12-inch water main.

"You don't appreciate it until you see it," he said. "This came out of nowhere."

He said crews are still trying to determine the cause of the crack.

The water main was installed in 1964 - five years before the interstate opened - but age is not believed to be a factor, Nelson said.

"Based on our findings, all joints and the casing appear to be in good condition," he said. It appeared the pipe may have been leaking slightly before the incident.

Heaving that occurs in spring and fall because of temperature changes has caused similar cracks, he said, and a major road project in 2012 may have compromised the pipe.

"It occurred over time, and we're at that place where we found out the time is up," he said. "We made the choice to replace the whole stretch of main, and it was a good choice."

The new main has been designed to withstand heaving and movement caused by construction equipment and cars and trucks. It includes multiple layers - a pipe inside a pipe inside a pipe, he said.

"We've got 160 feet of 14-inch HDPE (high-density polyethylene pipe) inside of a 20-inch HDPE and then put that inside a 24-inch old concrete casing under the road," Nelson said. "I think we're going to have good stability."

How much the repairs will cost won't be known for several days, he said.

Between 1.5 million and 2 million gallons of water leaked from the main.

A nearby resident called Oakdale police about 9 a.m. Sunday to report the leak after discovering water in her backyard. Nelson said crews had received an alert about three hours earlier that water pressure was dropping.

About 35 houses lost water service for several hours Sunday and about 6,000 houses experienced a loss of water pressure, Nelson said. There are about 11,700 households in the city.

As of Wednesday morning, only one resident was still without water, said Michelle Stark, a spokeswoman for the city.

"The city has provided him with bottled water and has arranged for accommodations to take care of his personal needs," she said.