PEORIA — Residents in a vast swath of the city and West Peoria are under a boil order until Tuesday night after a massive water transmission line burst Monday morning in the North Valley.



Torrents of water cascaded from beneath Jefferson Avenue just south of its intersection with Abington Street about 10 a.m. Monday, forcing Jefferson and Adams Street to close as swirling water gathered in steamy pools.



Single-digit temperatures soon transformed the roadways into ice slicks, prompting road crews to coat the pavement with a thick layer of salt.



The compromised 30-inch main drained water service from a large segment of the city — including schools and hospitals — and severely reduced water pressure elsewhere throughout the city's water system.



The official cause remained undetermined later in the day.



"It's hard to determine one cause of a main break — our main focus is getting the repairs made," said Karen Cotton, spokeswoman for Illinois American Water.



The age — 50 to 70 years old — and condition of the pipe may have played as prominent a role in the line's failure as the freezing temperatures, she added.



"We have seen an increase in breaks due to the weather," Cotton said. "We've had frigid temperatures, and we have seen some other breaks across our system."



Service was restored by early afternoon, and repair work on the main was expected to continue through Tuesday afternoon. Customers within the affected area, however, will have to boil water for 36 hours.



Cotton said Illinois American has about 50,000 local customers.



Illinois American is notifying customers about the boil water order in Peoria through an automated call to the customer phone numbers the company has on record, Cotton said. Customer notifications and updates will continue to be made through media outreach, Illinois American Water's website and social media.



Caterpillar Inc.'s Downtown headquarters closed Monday after losing water pressure, sending some employees home. The company anticipated reopening all offices Tuesday morning at regularly scheduled times, though cafeteria services would be limited. Employees were encouraged to bring bottled water.



Firefighters also prepared to bring their own water supplies in case of a fire while water service was disrupted. The city has 12 tanker trucks that hold 500 gallons of water, each lasting for up to five minutes while battling a blaze, Battalion Chief Jerry Malone said.



"It just depends on the size of the fire and how quickly we get there," Malone said, adding the main break was not an immediate safety concern.



Bottled water and hand sanitizer supplies were brought in to OSF Saint Francis Medical Center and Peoria School District 150 buildings affected by the outages, among other facilities in the impacted area. UnityPoint Health-Methodist postponed all scheduled surgeries until water service was restored.



For some, the scenario is one that is part of practice drills.



"We drill this all the time," said St. Francis spokeswoman Shelli Dankoff. "We didn't skip a beat."



Other establishments may not have been so fortunate. The Peoria City/County Health Department advised restaurants that lost water that they must close until sufficient pressure for sanitation equipment returned. Those establishments must then follow the Hazard Analysis and Critical Control Points bulletin for Food Establishments on how to handle the boil order and potable water supply.



Residents should bring water to a rolling boil for five minutes before using it for cooking or drinking, according to the water company. Tap water can be used for bathing, washing and other common uses.



Those subject to the boil order are all city residents south of Forrest Hill Avenue and all of West Peoria. Some customers north of Forrest Hill also might have received phone calls from Illinois American about the boil order as a precaution.



Water service was restored to all but about 20 Illinois American Water customers in the immediate vicinity of the break by early Monday afternoon.



The water company will arrange for a contractor to make temporary repairs to the roadway so that it can open to traffic, then return to the area when it is warm enough to make permanent repairs to the pavement.



The Illinois Department of Transportation oversees Jefferson in that area because it is part of a commercial route and part of Illinois Route 29. The highway department plans to route southbound traffic over the McClugage Bridge to Illinois Route 116 in East Peoria.



Motorists can then continue on Route 116 until it joins Route 29 just south of East Peoria or take Interstate 74 and the Murray Baker or Bob Michel bridges to return to the west side of the Illinois River.



About midday Tuesday, IDOT crews will open a temporary southbound route on Adams Street for all non-truck traffic from Van Buren Street to Hayward Street.



"There's going to be a closure (on Jefferson) for about a week or so," said IDOT District 4 spokesman Brian Williamsen.



One lane of Jefferson at Abington may open before the temporary fix is complete for local traffic only.



Matt Buedel can be reached at 686-3154 or mbuedel@pjstar.com. Follow him on Twitter @JournoBuedel. Laura Nightengale and Robert Connelly contributed to this report.