Helen Santoro writes: "Montana’s population has risen by 7.4% since 2010, and ranch lands across the state are being subdivided. But when land is divided, so are the water rights, creating an increasingly fractured landscape."

The article focuses on the example of the 14-million acre watershed of the Clark Fork River, which stretches from the city of Butte in southwestern Montana to Lake Pend Oreille in North Idaho. "Once it was dotted with farms and ranches, but in recent decades, tens of thousands of new houses have been built in the region," according to Santoro "From 1990 to 2016, over 1.3 million acres of undeveloped land in Montana was converted into housing, according to a 2018 report by Headwaters Economics."

Montana practices the "first in time, first in right" doctrine of water law, "meaning that the first person to use a water source has senior rights over newer users," explains Santoro. That means many ranchers and farmers have better claim to water, and the new homeowners have had some rude awakenings to that fact.