Water covers at least 70 percent of the world's surface. But 97 percent of it is too salty to drink [source: Frederick]. This, coupled with inequalities in water distribution and geographic availability, means water scarcity is a reality for many people. In fact, a lack of water affects four out of 10 people in the world [source: World Health Organization]. There can be serious health consequences from not having enough water. Sometimes it means people get their water from contaminated sources. Poor-quality water can spread diseases like cholera, typhoid fever or salmonella [source: World Health Organization].
Turning brackish or salty water into fresh water could impact both the meager rations of water and the ever-increasing demand. This is especially true for some coastal communities in the United States struggling with a fresh water shortage [source: California Ocean Resources Program]. In addition, desalination plants can provide a reliable water source even when a drought is afoot.
In 2009, there were more than 1,400 desalination plants operating in the world, producing more than 15 billion gallons of water per day. Another 244 plants are under construction, many of them in the Middle East [source: International Desalination Association]. However, the world's largest reverse osmosis desalination plant, which opened May 2010, is located on the Mediterranean coast of Israel [source: Dow]. And, construction is underway in Carlsbad, Calif., to create the Western hemisphere's largest desalination plant, estimated to produce 50 million gallons of drinking water every day [source: Poseidon].
Still, there's often a public perception that desalinated water doesn't taste good and isn't good for you. In Israel, for example, many people are increasingly reluctant to drink desalinated tap water because of health concerns [source: Mizroch]. But desalinated water -- straight from the tap -- is generally safe to drink. A study in Saudi Arabia, for example, found no significant differences between desalinated water served on tap and bottled water -- except for the fact that desalinated tap water doesn't leave empty plastic bottles behind [source: Ahmad].
But what if it were possible to carry a portable desalination device to produce your own personal supply of fresh drinking water? The idea may not be as far-fetched as you think.