I live remote and have to collect water at my house (too high for a well). I get ~15 inches of precip per year, relatively evenly spread (though May/June is the driest). Our water resources are very constrained - I have the option to haul water in, but it's an hour away and not fun. So I mainly collect from my rooftops. I can see two things happening:

1) The 20 year long descent into drought reverses. We get more snow, fewer fires and more people. Life on the edge continues.

2) The 20 year long megadrought continues and worsens. The SW states (NM, CO, AZ, NV, SoCal) will no longer be able to rely on Colorado's snow pack. This will initially cease all landscape supporting water to become illegal. Golf should become very expensive. To maintain viability for huge populations in 50-75 years, the states will have to combine resources and funding to move water from where it rains to the SW...this would have to come from mega projects to move water from the NW to the SW. If this doesnt happen, the SW will no longer be sustaining for this population and people will move - citing the cost of water to their houses as the water will only be useful for farming and food generation for everyone.

China is currently doing this for same reasons except in the opposite direction (SE to NE). I dont think our current liberal democracy will be able to solve this problem and that in 100 years, the SW will be lower in population than today.