California water - can it come from the ocean?

From the UC Berkeley lecture series found on Youtube:

Desalination, With a Grain of Salt: A California Perspective Heather Cooley: Senior Researcher, Pacific Institute. Long considered the Holy Grail of water supply, desalination offers the potential of an unlimited source of fresh water purified from the vast oceans of salt water that surround us. The public, politicians, and water managers continue to hope that cost-effective and environmentally safe ocean desalination will come to the rescue of water-short regions. http://www.lib.berkeley.edu/WRCA/ccow.html.