“As the world population increases, so does the demand for clean water. Global water consumption has increased nearly twice as fast as population growth in recent years. United Nations projections place global population growth at 30% by 2030, and as demand continues to grow accordingly, some projections place the water industry at a trillion-dollar market cap as early as 2020,” Abraham Ballin for Morningstar wrote in an ETF analysis. [Water ETFs: Next Big Commodities Investment Theme?]

PowerShares Water Resource Portfolio

Tisha Guerrero contributed to this article.