When California and six other Western states failed to meet a Jan. 31 federal deadline for deciding how to allocate water from the drought-ravaged Colorado River that supplies drinking water to 40 million people — 1 in 8 Americans — it was the Golden State that called the others all wet.

Citing the labyrinthine world of vested water rights, which guarantees it the most water from the 1,450-mile-long river, California objected to a plan backed by the other states — Arizona, Nevada, Colorado, Wyoming, New Mexico and Utah — on the grounds it should not have to bear an equal share of the federal government’s call for an annual reduction in Colorado River water of at least 15 percent.