Proponents of a plan to take millions of gallons a day of salty ocean water and convert it into a big, fresh drink for this thirsty county put out the welcome mat Saturday for more than 100 local residents and members of the San Diego League of Women Voters.

"Having our own source of water is important," said league co-President Beryl Flom, who said she organized the tour at the Encina Power Plant in Carlsbad to get more people informed and interested in the project.

"This business of importing our water (from the Colorado River) is risky," she said. "If the weather turns on us, we're going to be in trouble."

Visitors got a close look at a pilot desalination plant that has been chugging away in a small, fenced enclosure for a year, drawing water from Agua Hedionda Lagoon and producing about 40,000 gallons per day of drinking water.

That's only a shadow of what's to come, said Peter MacLaggan, senior vice president of Poseidon Resources Corp.

MacLaggan said company officials in cooperation with Encina owner Cabrillo Power hope sometime next year to launch a two-year project to build a giant-sized version adjacent to the lagoon to convert 100 million gallons per day of sea water into 50 million gallons of drinking water.

"This is a partial solution to our water-supply problems," said MacLaggan, adding the water produced by the plant ---- which could be expanded in the future ---- would be enough to supply about 300,000 people or 112,000 households.

With the growing population and increasing demands for a pure water supply to high tech and bio-med industries, "we need to look to the future," he said. "We're running out of options."

MacLaggan said that desalination has been used for more than three decades in many water-starved areas of the world, but making the Carlsbad project possible are improvements in technology which have driven down costs.

He said the pilot plant is producing drinking water "as we speak" at three-tenths of a cent per gallon.

"A decade ago, it cost twice as much," he said.

And, while the water initially produced by the plant will be more expensive than current costs to import water, he predicted in a decade the price of imported water and converted sea water will be virtually the same.

The pilot plant is also being used to conduct studies of potential impacts to offshore reefs and marine life when the salty, residual water from the plant ---- left over from the desalination process ---- is released to the ocean.

In a small trailer wastewater from the plant is continually circulated through a 120-gallon aquarium filled with living star fish, sea urchins, warty sea cucumbers, bass, lobsters, abalone, halibut and other creatures.

A year into the experiment, biologist Steve LePage said there has been no evidence of any adverse impacts. In fact, one of the most sensitive species --- the sea urchins ---- have reproduced.

Visitors for the most part said they were impressed.

"I can't see anything they are doing that is detrimental to the lagoon," said Bob Richards, past president of the nonprofit Agua Hedionda Lagoon Foundation. "Poseidon and we have a common interest. They need and want a clean lagoon, and we want a clean lagoon."

"I hope this (project) goes through," said Naomi Marblestone of Carlsbad. "We need it. We are so dependent on other people for our water."

Lagoonside residents Clifton and Martha Greagrey agreed. "I think it's wonderful," said Martha. "We'll have more and better water."

And, "we are running out of water," said Clifton Greagrey. "We have to get it somewhere."

"This certainly sounds like a solution," said Peggy Walker, who also lives by the lagoon. "It's good for the lagoon, and it's good for people."

Not so certain was Liz Kruidenier of Carlsbad. She said she was concerned what would happen if this plant is so successful, plants would be built up and down the state ---- each adding to the salinity of the coastal waters.

"I wonder what the cumulative effect will be," she said.