In Minnesota’s Twin Cities, there have been 40-plus days of subzero temperatures, which has caused the ground to freeze so deep that deeply buried water pipes are bursting, according to an article in the Star Tribune.
Conventional wisdom in the world of water supply buries the pipes below the freeze line. Historically that has been five feet in Chicago and seven or eight feet further north. According to the Star Tribune, “Public works crews have found frost piercing deep enough to freeze inch-thick service lines under streets and, in some cases, to plague much wider pipes 7 or 8 feet beneath road surfaces.”
Soil types can add to the problem. When clay soils freeze and thaw, they can literally push pipes to bursting.
Of course, these public water supply pipes feed the water supply to houses. And even houses built green have to worry about pipes freezing. Amica Today in its Winter 2014 issue had some advice for preventing frozen pipes. Homes built green seldom have to worry about whether their water supply lines are insulated, but that is the first step in preventing frozen pipes. The article recommends disconnecting garden hoses and installing protective faucet covers. If a pipe is vulnerable to freeze, deliberately letting a faucet drip can keep water moving fast enough to prevent freezing.
If a household pipe does freeze, do not use any kind of torch to warm it up because of the fire hazard. “Instead use a hair dryer.”
If everything fails, Amica warns that if pipe has burst, don’t let it thaw before it gets repaired.