You may remember that one of Jimmy Carter's first acts in office was mortally to offend some powerful members of Congress by publishing a hit list of costly federal water projects. The list was the opening round in a distinctive effort by Mr. Carter to reform the way the government has historically chosen and financed river and harbor improvements and irrigation works. His objective was to shift some appreciable part of the cost from the Treasury to the states and private beneficiaries.

The best that Mr. Carter was able to achieve in his four years was a kind of tie: not much money spent the old way, not much movement toward a new way, either. But President Reagan and budget director David A. Stockman took up where Mr. Carter left off -- and now they may have prevailed.

Both the House and Senate had included in the pending supplemental appropriations bill some funds to start new water projects. Their theory may have been that the bill was veto-proof because it also contains the funds the president has sought for the Nicaraguan counterrevolutionairies. Mr. Stockman warned that Mr. Reagan would veto the bill anyway. The Senate, driven by what one administration official called "a powerful thirst" for water funds, then agreed to new cost-sharing formulas. Senate agreement apparently will force the House to go along. Barge and ship owners, farmers, states and other direct beneficiaries all would pay.

The administration's interest in this has been mainly fiscal. The formulas are variations on its favorite theme of user fees. This is an intricate area. Almost all federal undertakings have private as well as public benefits. We are not always as eager as Mr. Stockman to shift costs to the private sector, but in this case the partial shift seems fair.

There are also good environmental reasons for adding to the felt costs of these projects. Almost by their nature, large water projects are often environmentally dubious. Subsidized irrigation projects also mask the true cost of water, which in the West is an endangered resource. Reform can do for water what OPEC did for oil: a higher price will encourage conservation.

The administration's victory is not complete. The new formulas will apparently be enforced through the appropriations process; they will not be inscribed in permanent legislation. The losing states and interest groups thus still have ways to wriggle free. We hope the president and Mr. Stockman stick to their guns.