OAKLAND -- KTVU News Health and Science Editor John Fowler says Bay Area residents may be drinking desalinated water from San Francisco Bay within five years.

Fowler says water officials tell him that the "time has come" for desalination and that environmental, technical and cost barriers are coming down.

Fowler says Bay Area water agencies are poised to unveil a plan to build a $500 million desalination plant.

A site has not been determined but one possibility is the current site of an East Bay MUD facility in Oakland.

The desalination plant would turn salty bay water into clean drinking water.

Supporters of the project say the plant could be running within five years.

Fowler reports the desalination plant could provide drinking water for five million homes and businesses in Contra Costa County, San Francisco County and Santa Clara County. Water officials estimate it would provide 10 to 20 percent of their drinking water.

Officials in Marin County may approve plans for a desalination plant of their own this summer. Paul Helliker of the Marin Municipal Water District told KTVU News "We have local reservoirs, we have some water from the russian river but we don't have many other options."

Environmental impact reviews are not yet complete for bay area projects, but officials predict no serious problems desalination may in fact reduce pressure on threatened fish species.

Fowler says this technology is likely to become more and more attractive as global climate change makes Sierra snowpack and rainfall less and less predictable.