Crews are installing a replacement metal collar after a break in a major pipe inhibited the supply of clean water to the Boston area.

Adding to the pressure Sunday was an unseasonably warm spring forecast, with the temperature predicted to reach 88 degrees. Restaurants in suburban Lexington shut down Saturday night, while police in Revere had to be called into a BJ's Wholesale Club after a run on bottled water.

The breach was reported Saturday about 10 miles west of Boston. It was in a joint in a 10-foot pipe carrying 250 million gallons a day from the Quabbin Reservoir to some 750,000 households.

Gov. Deval Patrick has declared a state of emergency and ordered residents to boil water, since some untreated water has entered the system. It remains safe for firefighting, showering and toilet flushing.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

BOSTON (AP) _ Crews welded a replacement metal collar Sunday they hoped would provide a quicker-than-expected fix for a break in a major pipe that cut off the supply of clean water to 2 million people in Boston and its suburbs.

Adding to the pressure was an unseasonably warm spring forecast for the area, with the temperature predicted to reach a summer-like 88 degrees.

There also were economic and social concerns: Restaurants in suburban Lexington shut down Saturday night, unable to wash dishes or serve customers clean water, while police in Revere had to be called into a BJ's Wholesale Club after a run on bottled water turned unruly.

The breach was reported Saturday morning in Weston, about 10 miles west of Boston. It was in a coupling holding together two sections of a 10-foot-wide metal pipe that carries 250 million gallons a day from the Quabbin Reservoir to some 750,000 households in 30 communities.

Officials initially said they hoped a repair could be made in days, rather than weeks, since the pipe has a complex design and needed custom-made replacement parts.

But the head of the Massachusetts Water Resources Authority said early Sunday that the necessary metal had been located overnight and welders immediately began fashioning the replacement part.

"The good news is we know the extent of the problem; we've got a solution to fix it," Frederick Laskey said. "As soon as the preparation finishes, they are going to start welding that repair piece back in place, and hopefully that'll be the solution."

While declaring, "I don't want to jinx it," Laskey said he hoped the part could be installed by Monday morning and then water pressure and water quality tests could be conducted "to make sure we can get the system back on and running."

Officials remained puzzled by the cause, since the break occurred in a stretch of pipe that was just seven years old.

"It could have been, you know, a design flaw, it could have been a construction flaw, it could have been that the product was faulty, it could have been something in our system," said Laskey. "There's just so many different variables that come into play here when you're dealing with that much strength."

Concerned about such a vulnerability in the system, the MWRA has been fashioning a backup system, but it is still three to four years from completion.

The MWRA immediately began tapping backup reservoirs to maintain water pressure for firefighting and sanitary purposes, but Gov. Deval Patrick declared a state of emergency and ordered MWRA customers to boil the water coming from their taps since it didn't meet federal clean water drinking standards.

Patrick also asked large supermarket chains to increase their bottled water orders and added that, if needed, the state can distribute emergency drinking water through the National Guard.

Boston police used bullhorns to broadcast the news as they drove up and down city streets, while electronic state highway signs flashed the same message.

At the height of the breach, the pipe was leaking water into the nearby Charles River at a rate of 8 million gallons per hour, according to state officials. The deluge forced up water levels on the Charles and the state had to activate pumps at a nearby dam, Laskey said.

The authority initially reported 38 communities were under a boil-water order, but some of those communities were only partially supplied by the water system and were removed from the list when they switched to local water sources.