Desalination, often thought to refer only to the removal of salt from seawater, actually removes virtually any mineral and most biological or organic chemical compounds to produce high quality water suitable for drinking.

Desalination has long been used in regions of the world where fresh water is in short supply. In fact, the process dates to ancient times when Greek sailors purified seawater by evaporation.

Desalination has evolved into a desirable water supply alternative by tapping the largest reservoir in the world - the Pacific Ocean. The technology, available for decades, is at work in many arid areas of the world including the Middle East, the Mediterranean and the Caribbean.

Desalination equipment is now in use in over 120 countries, including Italy, Australia, Spain, Greece, Portugal, Japan, China, India, Saudi Arabia, Oman, United Arab Emirates, Malta, Gibraltar, Cape Verde and Cyprus.

There are over 21,000 desalination plants worldwide, producing over 3.5 billion gallons of potable water a day. Overall, desalination plant capacity has increased exponentially over the past 30 years.

Saudi Arabia leads the world in desalination and relies on it to meet 70 percent of the country's drinking water needs.

The first large-scale seawater reverse osmosis (RO) desalination plant in the U.S. began operations in Tampa, Florida, early in 2004.

Historically, the high cost of water production has been the key concern related to large-scale seawater desalination. Technological advances have made desalination a viable water supply alternative. Manufacturers of the RO membrane filtration systems have been able to produce filters that last longer and at much lower costs than just a decade ago.

Desalination has also benefited from reduced operating costs in terms of electrical energy use - an important milestone since energy consumption can account for as much as one-half the total cost of the process.

Other cost-saving advances include construction of large capacity plants, co-location with power plant facilities and enhanced competition by using Design-Build-Own-Operate-Transfer project delivery.

Prolonged drought, dwindling sources such as the Colorado River and Bay Delta water, and more stringent treatment requirements are driving up the costs of traditional water sources and triggering the need for alternative local supplies.

Desalination is an environmentally friendly process that decreases the amount of additional water that would otherwise need to be imported from ecologically sensitive areas.