The need to feed up to two billion more people by 2025, booming industrialization in developing countries like China, and a warming climate seen threatening the world's most precious natural resource has investors serious about water.
"Regardless of what happens to the economy -- you can bet and bank on a predictable demand for water. It is a product that is essential to life," said Deane Dray, who analyzes water markets for Goldman Sachs in New York.
"People will largely pay 'whatever' because it is life-sustaining and there is no substitute. You put all those together, it is very clear why companies are enthusiastic about water."
ndeed, conflicts over water rights are already going on in dozens of areas from sub-Saharan Africa to the Middle East to Australia, India, eastern Asia and the U.S. Southwest.
One expert estimates that in the next 25 years trillions of dollars will be needed to upgrade fresh water and waste water technology and build new infrastructure to deliver water, with the bulk of that money to be spent in Asia.
"Infrastructure upgrades that are going to be required over the next 25 years on a global basis could be close to $20 trillion," said John Balbach, managing partner at Cleantech Group, a venture capital research firm in green technology based in Ann Arbor, Michigan.
Such huge costs mean a budget nightmare for governments, a reality check that water companies also factor in. Eventually, they say, people in all countries will have to ration water use by price and realize it is not a free resource for the world.