When you live in a a desert, water is more than survival

Dry look: ''Very quickly, we will run out of water,'' states Utah energy director James M. Bryne.

Wet look: ''We've got more water than we know what to do with,'' Salt Lake developer Wally Wright says.

Like a mirage on the desert, water supplies for the future of Salt Lake Valley come and go - depending on who is looking at them.

Second to Nevada in aridness, the state of Utah is home to the Great Basin, a broiled landscape penned in by the rain-stopping Sierra Nevadas on the west and the Wasatch Range on the east.

''Water is more like a religion than a factual argument around here,'' explains R. Thane Robson, University of Utah economist. ''For a politician to challenge a water reclamation project is like challenging the Mormon church here - it's sure-fire suicide.''

The Mormon conquest of this dry valley in the mid-1800s was pegged on diverting the streams of the Wasatch Range for an irrigation system controlled by the church.

The 20th-century focus of the water debate is the Central Utah Project (CUP), a chain of canals and dams begun in 1965 to lift water from the Colorado River basin over the mountains to Salt Lake - before California took rights to more of the river's flow. Originally priced at $324 million, the cost now tops $1.6 billion.

Placed on a ''hit list'' of federal water projects to be canceled under President Carter, CUP now engenders controversy under the Reagan administration, which wants states to pick as much as 25 percent of a project's tab.

With Uncle Sam backing off a bit, local CUP advocates are not so strong in their support. ''We still need the CUP, but its costs are too high,'' says Utah Gov. Scott Matheson. ''We can build it more efficiently without reducing the water designed for receivers.''

CUP is gaining new opponents other than environmentalists as production from the tar sands and oil shale of the Uinta Basin reaches commercial scale. Diverting all the water to Salt Lake homes, farms, and industry no longer seems the best idea for the Utah economy, which already has one of the highest water consumption rates in the country.

A second look, however, may open the project for total review. A joint statement of 10 national environmental groups in April called the Bonneville Dam part of CUP (which is only 18 percent complete) one of the ''worst (and) most wasteful and damaging'' federal water projects, claiming it was a huge subsidy by US taxpayers for a few users.

Over 80 percent of Utah's water now goes to farmers, mainly for marginal agriculture. Very soon, says Utah energy director James Bryne, industrial and energy projects will start competing with farmers for water rights, reducing much of the state's marginal agriculture.

Another source may lie underground. Only a few wells now feed Salt Lake, and much debate concerns how much water exists below the surface and whether it can be safely tapped without drawing in salt water. Another proposal is diking the Great Salt Lake's southeast section, which receives runoff from the Bear, Weber, Ogden, and Jordan Rivers. This would eventually create one of the largest freshwater lakes in the West.

Those who believe water is not yet a constraint say that air pollution in the Salt Lake valley is a more serious problem. Others argue that the new water is less critical than used water - sewage facility construction has not kept pace with city growth.

In January, officials watched with some fear as sewage plants reached full capacity at half time during the Super Bowl game.

County officials last year called for an immediate 16 percent reduction in water use, launching a ''water watch'' conservation program.

One new idea has only a few advocates in Salt Lake: Stop residential growth. ''What we must do is to stabilize the population. But those in elected office are afraid of the Mormon church and will not favor birth control,'' said Stanley Mulaik, retired biology professor of the University of Utah.

Yet, no one denies that someday demand will outstrip supply. ''Ultimately, water will be the limiting resource on Utah's resources,'' says Governor Matheson.