That is a very interesting question. All 3 of the states you mentioned pull much of their water from the Colorado River and there hasn't been enough rain of late feeding the watershed. We drove to Lake Tahoe via Las Vegas last year and their is a white ring around Lake Mead near Hoover Dam indicating its previous, much higher water level. Now it is at or near its historic low.
Seeing that ring really brings the water issue home - it is a visible reality.
And further proof of how, mainly CA, is destroying the CO river ecosystem, its tributaries and delta.