SAN DIEGO -- The heat is on to turn water off in San Diego County. That's the finding of an I-Team report on how short water supplies are being balmed on a small fish.

Most of San Diego's water is imported -- half comes from the Colorado River and the rest is from the Sacramento-San Joaquin River Delta in Northern California.

Cutting back on water use is not just about conservation. It's about a two-inch long fish called a smelt. According to the California Department of Fish and Game, the smelt population is down 90 percent in the past 20 years and it's now on the verge of extinction. This small fish is part of a larger system needed for human survival.

A 2007 lawsuit shook things up. "Delta smelt is increasingly in jeopardy" wrote U.S. District Court Judge Oliver Wanger who faulted U.S. Fish and Wildlife evaluations that "failed to consider the best available science" and ignored climate change.

As a result of the judge's legal opinion, the pumps that move the water through the delta now had to be used less because they trapped and killed the smelt. But less pumping means less water for the 25 million Californians who rely on water from the delta. The restrictions will begin easing at the end of June as the smelt migrate south. The pumping restricts return, when the smelt revisit the area in January.

California Gov. Arnold Schwarzenegger declared a drought state of emergency this year. Farmers have said they're losing crops, calling the Central Valley "a dust bowl." Over 100,000 acres of land are unplanted and crop revenue has dropped.

"You have a clash between protections for fish and water supply reliability," said Dennis Cushman of the San Diego County Water Authority. "We didn't arrive here overnight because of one fish species. We have a fundamental crisis."

Years of drought, years of water waste and poor planning have left California vulnerable to a water shortage.

"What we can do as a region is to be sustainable in the long term," said San Diego Coastkeeper's Bruce Reznik, who said the San Diego region is a desert and residents need to think about the current drought as a reality, not a fluke.

"We have more people in the region than we have potable water for," said Reznik.

A San Diego Grand Jury report on water warned: "Sober up San Diego -- the water party is over." The report said, "Even some experts and water authorities seem to believe there will always be enough water."

"We need to prioritize where our water comes from, how we get our water and what it gets used for and adopt policies that make sense from a long term sustainability," said Reznik.

According to the California Energy Commission, statewide, 19 percent of the energy, 30 percent of the natural gas and 88 billion gallons of diesel fuel are used each year to deliver water to California.

Opponents to the government protection of the smelt, say the plan is flawed because it only focuses on the smelt, but now more fish are at risk. More restrictions on water may be made due to population threats to salmon, steelhead, and sturgeon, among other fish.