"The worst crisis of all time, in my view, is the critical global shortage of fresh water," says " Larry Edelson. In Money & Markets, the resource expert offers four water sector plays.

"The world's water crisis is now getting worse by the day. And the global financial and credit crisis is merely one reason why. Another is the ongoing modernization of major parts of the world, which is increasing demand for water, while at the same time polluting it.

"Yet another is major droughts around the world, including in our own back yard, where 60% of the U.S. is officially experiencing a drought.

"New technologies and techniques for better water supply management and improved conservation on the demand side could potentially avert a worldwide disaster. And as a long-term investment, water is one of my favorites. For both its tremendous social cause as well as its profit potential.

"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.

This post is part of a special report, A Dozen Ways to Play an Obama Building Boom.

"Stocks in the water sector could soon flood their shareholders with a deluge of profits," says value investor Nathan Slaughter. In his Half -Priced Stocks, he explains, "Even in the 21st century, UNICEF reports that a staggering 1.1 billion in emerging markets still lack access to safe drinking water.

"And here in the U.S., the EPA has said we need to spend $275 billion to replace aging facilities -- including 800,000 miles of leaky, corroded pipeline that haven't been upgraded since the 1800's in some places.

"We see an incredible opportunities for the companies trying to combat the problem, particularly those involved with water distribution pipes, treatment facilities, purification technologies and other critical infrastructure.

"My top play in the sector is Veolia Environnement (NYSE: VE), a global juggernaut with $45 billion in annual revenues, operating on every continent.

"From humble origins supplying water to Parisians over 150 years ago, Veolia has grown to become the world's largest water utility. Today, it provides water and sewerage services to 130 million people in nearly 60 countries worldwide.

While many have opined that the water industry will be for the 21st century what crude oil was for the 20th century, water stocks got killed in 2007. Mostly due to a slowdown in residential construction, water infrastructure companies had large drops in profit. That being said, this industry is starting to show decent value.

My pick as the top performer for '08 is Mueller Water Products (NYSE: MWA). The company has taken measures to shore up their financial situation during the downturn in the construction cycle. They reduced expenses, increased cash flow and have strengthened their balance sheet. By trimming the fat and getting much leaner, Mueller is well positioned to benefit long term in the water infrastructure market once the housing market turns.

While I know this is controversial, and no one can pick a bottom, I think we will start seeing some bottom fisherman come in and start buying cheap real estate. If this happens, Mueller may well be a stellar performer in '08.

Aaron Katsman is the lead Portfolio Manager and Managing Director of America Israel Investment Associates, LLC. and Senior Editor of IsraelNewsletter.com. DISCLOSURE: The writer has no position in any stock mentioned as of 12/30/07.