A 12-inch iron pipe carrying water service for several hundered Warren residents broke early Sunday morning, leaving several hundered households without water for nearly 12 hours.

Accoding to New Jersey American Water spokeman Richard Barnes said the company doesn't know the exact cause of the break that occurred at about 4 a.m. Sunday, but such incidents aren't unusual in the winter as the ground shifts from freezing and thawing spells.

"February is generally the month in which we experience the most main breaks due to the soil shifting during freeze/thaw conditions," he said. "We're still analyzing data from yesterday's main break."

Age may be another factor—Barnes said about 15 percent of the company's nearly 9,000 miles of water pipes will be nearly 100 years old by 2020.

"The main was more than 40 years old and the age of infrastructure can be a factor as to why mains break,"he added.

The break follows an April 2011 water line break on Mountain Boulevard.

Barnes said repairs were completed by 3 p.m. Sunday and service was restored to all Warren customers.