ATWATER, Minn. (WCCO) — Steve Bomstad was on high alert this past winter. As the water supervisor in the city of Atwater, in west central Minnesota, he had his share of anxious nights — on winter’s most bitterly cold days.

“We’ve never experienced it before,” Bomstad said.

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Bomstad is talking about the brutal cold that cost other small cities, like Belgrade, thousands of dollars in costly repairs.

That’s because Belgrade’s municipal water tower froze twice over winter — one of many in the state to succumb to the prolonged deep freeze.

Municipal water experts say water towers tend to ice up and freeze during the nighttime hours when water demand is at the lowest point. People tend to be sleeping, not taking showers, washing clothes or running a faucet. Water demand falls to a drip and all that water in the steel tower just sits there, not moving or refilling with fresh (and warmer) groundwater.

“There might be 80,000 gallons up there,” Bomstad said, as he peers 125 feet skyward to the top of his water tower.

The city’s tower froze back in 2009 during another extended cold spell. That, too, was costly when the city had to hire an outside contractor to climb into the tower and use hot steam to thaw it. Due largely to that experience, last fall Atwater had contractors install a mixing system.

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That mechanical process now keeps water moving by cycling the pumps, which carry up the much warmer groundwater. Moving water is much less prone to freezing.

Bomstad adds the secret to preventing frozen towers is, “put the warm water in and draw it out as fast as you can reasonably do. Or else you have to get a mixing system like we did.”

Still, the new mixing system couldn’t prevent trouble underground. In Atwater, like all across the state this winter, deep, deep frost ruptured water mains and froze residential water service lines.

“We found frost five to six feet deep in the road where we had a main break,” Bomstad said.

And in mid-April, when it appears that spring is abundant, some residents are still without water. And they will remain without city service until the ground thaws and repairs can be made.

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But leave it to small town ingenuity to use tanks mounted in the back of pickup trucks and fire tanker trucks to supply what the water towers can’t.