A year ago, shortly after he tried to cancel 18 controversial dams and water projects, Jimmy Carter called for "comprehensive reform of water resources policy, with conservation as its cornerstone."

Last week, Interior Secretary Cecil D. Andrus, asked how he viewed Carter's directive, replied: "To reform? No. A major effort to review ans see where we were, but not as a comprehensive aspect to reform . . . A great deal more has been made of it than should have been."

Andrus' remark is indicative of a widespread sense of lowered expectations as the administration's closely held water policy package comes together. It also reflects the extreme political sensitivity of water as an issue.

Western states, which face critical water shortages, are jealously fighting off any federal intervention. And any attempt of revision could affect the billions of porkbarrel of dollars that the federal government dispenses each year for dams, irrigation, navigation and flood control projects.

After months of intense political pressure, key administration officials are reluctant to recommend any revisions that would evoke strong opposition from Congress or the states. For examples:

A step which Andrus and others called "imperative" last year - an increase in discount rate used to analyze federal water projects - has been all but dismissed as politically unfeasible.

Also unlikely are strict conservation measures that would make groundwater regulation, water meters and irrigation efficiency conditions of federal water funds. Instead, a grant program for state water resource plans is favored.

Although a coalition of 25 environmental groups called on Carter last week to halt construction of 20 major water projects, any ongoing projects are apparently taboo after last year's "hit list" uproar. Billions of dollars worth of projects now under construction will probably be exempted from any water policy changes.

Such a cautious approach reflects Andrus' concern for states rights. "There are no illusions that the federal government can impose effective reforms in water policy," he told a group of state legislators last week. "We can't and we don't want to . . . Our water policies - state and federal - are so enrwined that we must act in concert if we are to act at all."

Many water experts, however, doubt that there can be an effective overhaul without forcing states to change laws that encourage water and overappropriation.Groundwater tables are dropping drastically all over the west. Competition among farms, cities, industries and Indians has become intense. Droughts have forced rationing and economic disruption.

While even Carter would not advocate the kind of broad legislation that dealt with water and air pollution in the early 1970s, he might still choose some of the tougher water policy options, despite some advisers' recommendations. The Council on Environmental Quality and the Office of Management and Budget, which have been working on the policy with Interior may favor a bolder approach. The Domestic Council and Vice President Mondale are expected to emphasize the political hazards.

Carter is scheduled to make a final decision next month, although it may be delayed by a North Dakota court ruling last week requiring an environmental impact statement on the recommendations. The policy involves dozens of complex options, each with economic, environmental and political aspects.

In the last few weeks, Andrus and his aides have met frequently with western governors to work out a compromise policy. "Not compromising on principles," Andrus emphasized. "But on mechanics . . . (It is) and understanding of what is double and attainable."

Andrus acknowledges that his thinking has changed on the discount rate - but he says he has come up with a less controversial means to the same end. Changing the rate - a complicated formula used to calculater the benefits of a project - would eliminate some of the expensive, environmentally damaging boondoggles that have characterized decades of federal dam building.

Instead, Andrus has proposed to the governors that states pay 10 per cent "up front money" for federal water projects. Traditionally, the federal government has footed the entire bill - now roughly $5 billion a year. A small percentage of the costs is paid back over the years through irrigation and electric charges.

Andrus wants to apply the 10 percent formula to the 823 Army Corps of Engineers and Bureau of Reclation projects, worth $34 billion, that Congress has authorized but not yet built.

If state legislatures had to appropriate money, "Their constituents would take a look, the light of day would be shown upon them and the people would either accept or reject the projects," Andrus said, "The states are as aware as we that you can't build 828 projects worth 34 billion bucks."

One critical test of the water policy will be what overall proportion of project costs beneficiaries are required to pay back. So far, water projects have tended to benefit small constituencies at taxpayer expense - a group of farmers gets millions of dollars of subsidized irrigation, barge owners get free navigation advantages, developers build on flood plains below federal dams.

Each of the 25 federal agencies that build water projects has a different cost-sharing formula - which together, result in the recovery of less than a quater of the federal investment. Environmentalists want Carter to require beneficiaries to pay back 100 percent of the costs. But water policy planners are lending towards a more modest 25 percent formula.

A key question is whether Carter will try to apply new cost-sharing rules to the $34 billion in authorized projects - a move that would certainly spark congressional opposition.

Also in question is whether important changes in the criteria for building water projects will apply to the $34 billion backlog. The changes will probably make conservation a prerequisite, reduce exaggerated benefits such as flat-water recreation, and give equal weight to non-structural projects such as flood plain parks instead of dams.

The administration has already begun steps to raise the price of water - a move that will encourage conservation as well as fiscal responsibility. An audit of California's Central Valley's Westlands water district contract, Interior is trying to hike the price of federal irrigation.

Another test of Carter water policy is whether the administration aggressively tries to renogiate long-term contracts that sell extremely low-priced water, or simply waits for the renewal. Roughly 90 percent of the water used in the west is for irrigation, so the effect could be considerable.