The Washington region's bickering response to the drought is undermining its conservation efforts just as similar battles over water did in the West, a group of environmentalists and Maryland officials warned yesterday from near the banks of the depleted Potomac River.

Across the country, water officials in California and Rocky Mountain states have learned hard lessons about trying to cut water use without a clear political consensus on the need to do so. In Southern California, confusing calls for conservation have resulted in no savings, while in the Bay Area, one water board's urgent plea to cut water use proved so successful it almost bankrupted the utility.

Now national water experts say the Washington region is about to repeat some of the West's mistakes unless political leaders establish uniform conservation measures that cut across city and state boundaries. Maryland, Northern Virginia and the District all draw water from the Potomac River, but so far only Maryland has imposed restrictions on the communities that rely on it.

"Those water wars are moving here," said Rebecca Wodder, president of American Rivers, a national conservation group. "And we need to be prepared. We need to start seeing the big picture."

Wodder's comments came during a news conference along the trickling Muddy Branch stream where it empties into the Potomac in Montgomery County. Joining her were other environmentalists and Maryland political leaders to argue for a change in the rules that govern the flow of the Potomac, now running at less than half its capacity.

The group, including Montgomery County Executive Douglas M. Duncan (D), asked that water be released from reservoirs to protect the river's wildlife sooner than currently required. Regional agreements demand that water be released from the Jennings Randolph Reservoir in Western Maryland if the Potomac reaches a flow of 100 million gallons a day -- about half its current level measured below Little Falls. The last release was Tuesday.

"When are they [officials in Virginia and the District] going to say we have a problem?" Duncan said. "At what point do the reservoirs have to hit before they see this is a problem? When they run dry?"

Virginia officials say that the reservoirs were built for just such a drought and that mandatory restrictions are unnecessary now.

"Our position is that there's adequate water supply," said Jim Warfield, executive director of the Fairfax County Water Authority.

Mayor Anthony A. Williams said he, too, does not regard the water supply as critically low yet.

"The District ought to be taking voluntary steps, and residents should be conscious of a water problem," said Williams, who noted that Maryland communities receiving their water from sources other than the Potomac face more dire circumstances. "We don't have the same problem that they do."

Such regional conflicts and murky calls for conservation have been the hallmark of failed campaigns in the West. Western water officials say mandatory and voluntary limits have proved highly successful only in cases in which the means and ends were clearly explained to consumers.

"This is a public relations issue," said Donald Wilhite, director of the National Drought Mitigation Center in Nebraska. "Where you have those sorts of sharp lines between authorities for water supply, there really does need to be a greater degree of coordination between" them.

To cut consumption in Southern California during the early 1990s, the Metropolitan Water District used a billboard campaign that called on households to limit water use to 100 gallons a day. Just one problem: No one knew how much they used already, and the campaign was a bust. An average person uses 68 to 70 gallons each day washing, flushing and cleaning, but a survey of the utility's customers later found that many thought they used just 10 gallons a day.

Sometimes ill-defined campaigns to save water work too well. In the towns and cities lining the eastern shore of the San Francisco Bay, the water utility called for conservation a few years ago to disastrous effect. Berkeley and Oakland are infused with an activist spirit, so when the East Bay Municipal Utility District asked customers to clamp down on water use, the response was amazing.

Water consumption dropped by almost 40 percent -- far more than agency officials expected -- and the utility's revenue plummeted. Facing possible bankruptcy, the utility's elected commissioners boosted water rates not once but twice, infuriating customers who felt they were being punished for a job well done. Several of those commissioners were ousted in the next election.

The confusion among Washington area water users, many of whom have received little if any information on the need for water conservation, is reflected in the disparity in consumption. Maryland residents have cut back use by about 10 percent since Gov. Parris N. Glendening (D) imposed mandatory restrictions -- more than has been saved under voluntary calls in Virginia and the District.

As droughts have worsened, some western water officials have resorted to raising rates to discourage use, a tactic that has proved less successful than other methods. In Santa Barbara County, several water districts share Lake Cachuma, not far from where Ronald Reagan kept his western White House. The county, along with the rest of the West, suffered a severe drought from 1987 to 1992, and the lake floor cracked like a desert river bed.

The response from the county's water districts varied. In Goleta, a northern suburb of Santa Barbara City, water officials called early for a 15 percent voluntary reduction. They gave away low-flow shower heads and toilets or sold them at big discounts. They permitted appeals for hardship cases, but only if the customer allowed a home audit to determine ways to save water. The result: a 30 percent drop in use.

But Santa Barbara City officials did not call for voluntary restrictions, hoping a heavy rainfall would take them off the hook. Soon, though, the city had used its small share of the falling reservoir, and the City Council called for a 50 percent mandatory reduction in water use. That was followed by a quadrupling of water rates.

"Some rich people kept doing whatever they wanted. The poor people and the environmentally aware cut back because they knew it wasn't a matter of paying for it but that there was no water," said Deborah Braver, a water conservation specialist with the California Department of Water Resources. "Within weeks, people stormed the council meeting and said people shouldn't be able to buy their way out of shortages."

The Washington region is also at odds over how to enforce water rules. Even neighboring counties within Maryland are taking different tacks to ensure that residents comply with the new state water rules. Montgomery is threatening civil fines for flagrant offenders; Prince George's County plans only to warn people. But in places not riven by such differences, the results have been more successful.

In May 1977, Denver water commissioners imposed mandatory restrictions limiting residential lawn watering to three hours every third day. Denver Water hired college students to patrol neighborhoods mornings and evenings looking for scofflaws.

"We called them water ambassadors, but everyone knew what they were," said Elizabeth Gardener, Denver Water's manager of water conservation. "Water cops."

First-time offenders received a $10 service charge on water bills. If customers were caught a second time, Denver Water installed a plug in their residential service line that slowed tap flow to a trickle for a week. Those rules were left almost entirely in place for four years, and consumption dropped an average of roughly 20 percent.

"We don't make it a big deal to tell customers it's no longer mandatory, and some people still think it is," Gardener said. "Only if they ask me straight will I tell them it's voluntary."

Staff writers D'Vera Cohn and Michael H. Cottman contributed to this report.