Chuck Dale, Fairfield’s water supervisor, wasn’t satisfied with the rain that blew across northcentral Montana Wednesday. It wasn’t nearly enough to refill the depleted wells in the 800-person town about 35 miles west of Great Falls.

“Take a 30-foot cylinder, fill it full of dirt, pack it as tight as you can, pour six inches of water in the top and see what comes out the bottom. That’s the best way to put it into context,” Dale said. “You’re never gonna see anything drop out the bottom.”

The current water shortage — brought about by a combination of failing, decades-old infrastructure and a worsening regional drought — has strained the water supply of residents and the irrigation systems of local farmers.…