The WSJ takes a look at water investments, which, despite a seemingly rock-solid thesis, haven't held up as well as other scarce commodity investments:

Water use drops in a recession: 40% of fresh water in the U.S. is consumed in industrial applications. That is why many water utilities have fallen recently on recession fears.

Two of three exchange-traded funds that track water-related stocks have sunk since their mid-2007 debuts. The third, First Trust ISE Water Index, is up 4.1% since its May 11 launch. But measured since June 13, after all three began trading, it has posted a gain of 1.9%. Over that period, Claymore S&P Global Water ETF (CGW) has lost 6.3% and PowerShares Global Water Portfolio (PIO) dropped 11.9%, compared with the S&P 500-stock index's loss of 13.2%.

As for the real water economy:

The economics of water treatment and delivery itself look compelling. An acute shortage of clean water in many regions has been worsened by population growth and by competition from industry and agriculture.

More than one in six people lack access to safe drinking water, according to the World Water Council. Global spending to treat and purify water, and to improve the often-dilapidated infrastructure that stores and distributes it, amounts to hundreds of billions of dollars a year, and rising.

Investors can't trade water like other commodities, because it isn't priced on a global market. It is heavy and the cost of transporting it is many times its value, so it lends itself to regional markets.

The other thing is, in the developing world, people probably drink too much of it. 6-8 glasses a day? Gimme a break. 2-3 is fine.