"Warren Buffett's Berkshire Hathaway revealed a new position in Nalco Holding (NYSE: NLC); it's my favorite pure play on water filtration," says Chris Mayer in Daily Wealth.

"With a $1.6 billion market cap, Nalco is a small-cap stock, but it's actually one of the world's largest water-treatment companies. Customers use Nalco's products and services to prevent corrosion, contamination, and the buildup of harmful deposits.

"Buffett picked up 8.7 million shares. That makes Berkshire the second-largest shareholder in the company, with a little more than 6% of the shares.It's easy to see what Buffett likes.

"It's no secret that the world is facing a severe water shortage; many experts, believe the next major war will be fought over water, not oil," says Marc Lichtenfeld.

The senior equity analyst for the top-notch growth stock advisory, Xcelerated Profits Report explains, "Desalination is likely the only way the world's water needs will be met. And one company that will benefit is Energy Recovery (NASDAQ: ERII).

"Just how severe is the shortage? Demand for fresh water will exceed supply by 50% in 2025, with one-third of the Earth's population living in countries with water scarcity. The bottom line is that if we plan to feed and provide water for everyone, we're going to have to find a way to use more water more efficiently.