By catchment I meant cistern, its the same thing. Everyone has been harvesting rain for thousands of years for household use, it may be time to revisit US water rights law and think them through again. We haven't always had thousands of gallons flowing out of our taps. If average rain fall is a half or a quarter of what it was when the law was developed to protect the watershed then hydrologists and engineers - and politicians - have to rethink priorities. People are shocked when they don't have legal rights to harvest rainwater coming from their own roof, but it goes back to gravity and elevation and principles like the farmer downstream or downhill needs water too. If your cistern is collecting what will otherwise turn into storm water, you have to consider downstream effects. In the PNW with 38 inches of rain per year mostly that's endangered salmon runs, for now. If we hit 22 per year avg rivers and lakes subside and we have salinization issues too - and no more fish. It can be a big deal for someone to lift out thousands of gallons a year, much less a city of 70,000 doing the same thing. Better learn from our agricultural areas and mete out water in newly arid areas before it becomes a bigger thing.

Without getting into the whole Billionaire Monetization and Agenda 21 control politics of their attempts to control the worlds water resources, whereby you are not allowed to collect rain water on your own property without being subject to heavy punitive fines, what would be the legal situation of owning a Skywater 14

http://www.islandsky.com/products/home-and-office-water-making-machine

You will need a 3-4 kW solar PV installation though, to power it. As with everything, money can solve a lot of problems when it comes to personal survival and preparation to be equipped to survive.

I had seen these in Hawaii but did not know what they were called. Very interesting. I could see setting up a sump pump and basin under the house to receive and pump laundry water to two of these and then use them for watering.

John Wesley Powell had it figured out almost 150 years ago, but nobody wanted to hear it from him. (A good read is "Beyond the Hundredth Meridian: John Wesley Powell and the Second Opening of the West" by Wallace Stegner.)

In the future the western US simply does not have enough water to support our current lifestyle with projected population increases. I find it very difficult to believe that desalinization (or towing icebergs) will be practical on the scale required. Our lifestyle will change, whether we like it or not. I'd like to think we could be proactive and manage that change in a positive way, but I'm a bit cynical about the chances of that. People resist any change from the status quo. But status quo is not sustainable in the long run.

+1 to Stegner's work. It is a most thoughtful and thorough study of a very important figure in western US history..

The fact is, we have transported cultures and lifestyles developed in places with plenty of water into the semiarid western US and presided over a massive population growth in the last half century. Something will have to change. Probably we will see changes in lifestyles, better hydraulic infrastructure,and a smaller population as we adjust.

Someday in the future, Hikermor III will walk into the iceberg store in Anchorage (either Bergs R' Us or Starbergs) and say:

"Hi,I'd like an iceberg to go, please." AKSAR III will respond, "Fine! They come standard with navigation lights. Would you care for a topping of slush? Helps with the melting...."

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Indeed we have. What is even more scary is that we may have brought in these cultures and lifestyles during a period when the west was unusually wet.

Research is suggesting that the the period when the western US was settled may have been a good deal wetter than the long term average. See Hundred Years of Dry: How California’s Drought Could Get Much, Much Worse. Various lines of data suggest that over the long haul, the west was a very dry place indeed, and the 1800s and 1900s have been an unusually rainy spell. From that article:
Note that this is looking at long term past history, before the industrial age. If one considers the possible effects of anthropogenic global warming on top of these long term trends....... as one of my old professors always said.... "I will leave that as an exercise for the student."

I believe WA state just changed the law to now allow rain barrels.

Which seems okay to me, in western Washington the average holding is less than 1 acre, most suburban homes are on .25 acres, they can get by with gutter harvesting into a 55 gallon drum to sustain their home garden through a summer, which is usually dry. If we all respond by starting up 2-3 month gardens, which is the average growing season here, many will fail but at least they won't consume too much water and a number of us can supplement our veggies for what is now too costly to produce inexpensively in California. Blueberries from Peru are popular in stores at 7.99 for ~2 pints. We're used to it. A fair amount of food production has already shifted to Mexico and points south which actually have more sustainable weather patterns compared to Calif drought. Until the costs of transportation go up. There's no free lunch. People have been telling us for quite a while...

This year I'm planting hops, which is about the only crop I've succeeded in growing in 98004 in the past 20 years. Hops smell really nice in hot weather, and with my coffee roasting in the garage my neighbors say they get really thirsty all the time. I know a network of home brewers who will buy my hops, or trade them for some nice veggies. Or I could go back to my college days and homebrew.

"Note that this is looking at long term past history, before the industrial age. If one considers the possible effects of anthropogenic global warming on top of these long term trends.....".

It looks like my profession of archaeology has bright future prospects as rainfall amounts regress towards the long term mean. And we can see the effects of rainfall variation
on past human populations in the west, although many other factors come into play.

I'm still holding out for icebergs. After all, we have been importing Alaskan liquids for quite a while, and icebergs are less polluting than the Exxon Valdez. Need I say that developing the iceberg technology will be a titanic undertaking?

What's the difference between "anthropogenic global warming" and just "global warming"? Are we still warming or is the term dejeur climate change because of recent cooling?

My personal belief is that the "anthropogenic" term should be dropped from use in this forum. It's a tad divisive.