There's a Scottish proverb: "They speak of my drinking but never question my thirst."
While the author wasn't likely talking about water back then, it's appropriate now.
Water is a precious commodity; an absolute necessity to individuals, farming, and industry. As our population ages and gravitates to warmer climes, and the middle class grows around the world, this is one sector that will get a lot more attention in coming years.
The three water positions from Rick Rule are great plays on the favorable supply/demand dynamic of water and water rights, especially in the southwestern U.S.