Another reason investors are interested in water is the fact that Americans are paying 75% more for the resource then they were in 2012, reports Mac Slavo for ETF Daily News. A recent study by USA Today found that at about 100 large cities in the US, the prices hikes are so significant they are having to cut other expenses to afford it.

Furthermore, water rates are predicted to go up 5%to 15% per year for various reasons. Aging water system repair, more expensive costs to create potable water, and rising health care and pension costs for water department employees are just a few of the reasons water will cost more in the near future. [ Chart of the Day: Water ETFs]

PowerShares Water Resources Portfolio

Tisha Guerrero contributed to this article.