The city of Blaine caused dozens of private wells to run dry last summer after wrongfully pumping hundreds of millions of gallons of water from three wells without a permit, a state investigation found.

The Minnesota Department of Natural Resources announced the findings Tuesday after a monthslong investigation into 50 complaints from homeowners who temporarily lost water during the height of the 2022 drought. The city's pumping was the main reason that 47 of those homes lost water, the DNR found.

Another 27 complaints from private well owners who lost water are still under investigation.

"This is the largest number of complaints in one investigation that the state has done," said Randall Doneen, DNR conservation assistance and regulation section manager. "It speaks to the challenge of a growing community trying to develop a treated sustainable water supply when the neighboring community is almost all private wells."

The city will have 60 days to work out settlement agreements with each of the private well owners — those settlements typically cover the cost of the work it took to restore water to a home.

"We're looking at how we can move forward to make this right for everybody," said Dan Schluender, Blaine's city engineer.

The costs for well owners varied, from a few hundred dollars to a little more than $6,000, depending on how much work was needed. All together, the 47 well owners spent $97,000 lowering pumps, drilling deeper wells or doing other work to get water back in their homes, according to the DNR.

The number of households that lost water is unprecedented in Minnesota. The DNR typically receives five well interference complaints in a year.

Blaine first started using the unpermitted wells in summer 2021, according to the DNR. They were used temporarily as demand surged in the summer, when the city's water use jumps from about 6.5 million gallons a day to a peak of 18.5 million gallons.

The problems didn't really begin until 2022, the second straight year of drought.

Home wells started to run dry in July. As complaints poured in, the DNR looked at the city's new treatment plant and learned in mid-August that Blaine was using three new wells without a permit. The city shut them off immediately, and the water table climbed back up.

The city pumped about 380 million gallons of water on the three unpermitted wells in 2022, said Ellen Considine, hydrologist supervisor for the DNR.

There was a misunderstanding with the city's permits, Schluender said.

Blaine had recently dug four new wells as part of a nearly $30 million upgrade to its water system, which included a new treatment plant. The DNR gave the city a permit for one well, but the city believed the permit was for all four new wells, Schluender said.

Water was quickly restored to all well owners. Most homes lacked water for a couple of days, according to the DNR. Some had to wait as long as a week or two until a driller could get on-site to deepen their wells.