But what should companies be doing about it—now? Just like with energy efficiency, there is much low-hanging fruit to be picked where water is concerned.

Landscaping, which consumes more than 50% of urban water, is just one place to start.

Surprisingly, automatic irrigation systems can contribute to either the problem or the solution. Currently, there are about 60 million of these automated watering systems across the U.S., used by governments, real estate developers, suburban office parks and retailers. Most operate on timers—that is, they water the grass or plants every few days for a set number of minutes, regardless of whether it has been raining or not or the weather is sunny or cloudy.

"This current technology makes about as much sense as having a timer instead of a thermostat in your house," says Chris Spain, the founder of a company called Hydropoint, which offers smart irrigation systems.

Water conservation, cost cutting and increased yields

Born from parched necessity, a new crop of hydrological innovations, featured in EDF's Innovations Review 2009 has sprouted up. By combining weather data, soil sensors and wireless communication, companies like PureSense, Hydropoint, and Acequia are helping companies use less water—and save money—by precisely scheduling irrigation for commercial landscaping, as well as for agricultural crops.

The city of Newport Beach, CA., an early Hydropoint customer, says it reduced landscape runoff (and associated pollution) to its popular beaches by 70%. Other Hydropoint customers include Amazon, Advanced Micro Devices, Cisco, eBay, Lockheed Martin, McDonald's and Wal-Mart.

PureSense markets to farmers, particularly California's big growers of grapes, nuts and fruits. Its customers include The Wine Group, which says it increased its yield three years in a row, by 20 to 60%, and reduced its operating costs by 15% after installing a PureSense system.

On the financing side, Austin, Texas-based Acequia uses a model similar to energy service companies (commonly-known as "ESCOs"). Acequia fronts the capital costs of putting in the system in return for a cut of the savings its clients (including American Airlines and Hilton Hotels) realize from reduced water bills.