I saw several signs like these on the trip up to San Francisco for the Thanksgiving holiday. After about the third or forth time, it struck me that this is an example of Milton Friedman’s dictum that “If you put the federal government in charge of the Sahara Desert, in five years there’d be a shortage of sand.”

If you put California in charge of the ocean, in a generation or two you’ll have a shortage of water. Obviously it’s not quite as simple as that, because the near-infinite water supply about forty miles to the west is salt water. But still: the basic technology to turn salt water into usable water is something that’s been understood for centuries.

Throughout the world, however, governments control water usage. In the United States, almost all water supplies are government-managed. Even the act of capturing rainwater is heavily regulated in some parts of the country.

Put governments in charge of a planet whose surface is 70% water, and you’ll end up with a shortage of water.