Advances in reverse osmosis membrane technology are convincing more and more cities to invest in cleaning their own used water instead of piping it in from far-off reservoirs.
"A non-profit organization called the Affordable Desalination Collaboration formed in the state of California as a public/private venture that has funding from some of the municipalities like Orange County, West Basin, and the city of Santa Cruz. It also has funding from the state of California's Department of Water Resources, the U.S. Bureau of Reclamation, and then some of the industrial companies."
"For example, when the Santa Barbara seawater R.O. system was built in the early 90s, it cost about four times what it currently costs to desalt seawater-seawater desalting costs only 25 percent of what it did just 15 years ago. So, we found out very quickly that the technology has improved and is more energy efficient..."
"...osmotic pressure represents a potential source of energy. That was postulated in the 1970s by the originators of the reverse osmosis concept but at that time the technology didn't exist to capture that osmotic pressure and turn it into power. Today, because of technological improvements, it is conceivable that we will be able to capture the osmotic pressure from seawater and make it a source of power."