Cally Carswell has a story in the latest High Country News about domestic groundwater wells in Washington state that nicely illustrates a common problem throughout the western U.S., including here in New Mexico.

In Washington (like in New Mexico), you can legally drill a well to serve domestic needs – essentially a single house. Individually, any one well doesn’t sufficiently diminish an aquifer or drain surface water enough to make it a problem. Collectively, though, it’s becoming a big issue:

Under the doctrine of prior appropriation, in which the oldest claims  are first in line for water, domestic wells, like all groundwater rights, should fall behind surface water rights. But while Washington law recognizes that groundwater and surface water are connected, the state restricts groundwater withdrawals only if their impact on more senior rights can be shown. Such connections are especially hard to prove for exempt wells, which are scattered and individually draw small amounts of water. So they operate unrestricted even during extreme droughts.

We haven’t had conflicts here in New Mexico like the ones Carswell describes, but the legal issues are similar. State statute here was interpreted for years as explicitly exempt such wells from regulation, but a state court decision on the Mimbres River last year ruled the law conflicted with the constitutionally enshrined doctrine of prior appropriation because of the way groundwater pumping diminishes surface flows. Michael Campana had a nice writeup on the issues last year.

(h/t Elaine for sharing the HCN story)