The leaders of Washington and its surrounding suburbs yesterday agreed to study whether the region should establish a more uniform response to water shortages in times of drought.

The unanimous vote by the Metropolitan Washington Council of Governments board of directors follows a disagreement pitting Maryland against Virginia and the District over whether water use should have been restricted in recent weeks in communities supplied by the Potomac River.

Only Maryland imposed mandatory water restrictions in response to the drought, while District and Virginia officials relied on voluntary calls for conservation. Gov. Parris N. Glendening (D) lifted the bulk of Maryland's restrictions last week, and yesterday he lifted the ban on outdoor burning in four western counties.

A resolution calling for the study of how the region should respond--part of a broader examination of the region's water supply--was proposed by Montgomery County Executive Douglas M. Duncan (D), who has been a chief critic of the response to the drought by Virginia and the District.

"As a region, we're not doing what we need to do," Duncan told the board, comprising elected officials from the District and its suburbs. "We are sending confusing mixed messages to the public."

Under the resolution, a COG task force will study whether rules should be created that would automatically trigger water restrictions for all regional jurisdictions when the Potomac River dwindles to certain levels. Duncan said he believes that once reservoirs are tapped to boost the Potomac, as they were this summer, jurisdictions that draw from the river should call for increasingly strict conservation measures.

The resolution also calls for suggestions on how to give elected officials more say over when restrictions are necessary. That decision now rests largely with water utilities, which make money selling water.

The study, due in November, also will consider whether the threshold requiring the release of water from reservoirs into the Potomac is adequate. Under current water-sharing agreements, a reservoir release is triggered when the Potomac flow dips below 100 million gallons a day, though Duncan and environmentalists say that is too low to protect river wildlife.

Yesterday's resolution passed only after it was edited to remove references to the disparate responses by the three jurisdictions, as well as other passages that Fairfax County Supervisor Gerald E. Connolly (D-Providence) said could give the impression that "someone was right and someone was wrong in managing the drought."

The description of a broader water-supply study as "necessary" was changed to "timely." Calls for a "unified" response to drought became "coordinated." And any future rules governing water supply would take effect only in times of drought "emergencies," a change that could make future water-sharing agreements more difficult.

"I'm not prepared to say that 1999 exhibited the characteristics of an emergency," said Fairfax County Supervisor Robert B. Dix Jr. (R-Hunter Mill).