Maryland Gov. Parris N. Glendening declared a statewide emergency today to deal with the effects of the worst drought in 30 years and called on residents to voluntarily conserve water as he weighs imposing the state's first mandatory restrictions.

"We will have to have some mandatory restrictions. It will impact the average Marylander," Glendening said. "We expect the drought to get worse before we see relief. . . . We're all going to have to make sacrifices."

Glendening (D) made his announcement at the edge of the Liberty Reservoir in Carroll County, where water levels are 24 feet below normal. The reservoir serves much of the Baltimore area.

Conditions are not as dire in the Washington area, primarily because much of the region draws its water from the Potomac River. Though the Potomac is running at only half its usual volume, officials at the Washington Suburban Sanitary Commission said the river's supply of water was more than adequate to meet the needs of suburban residents through mid-November even if there is no additional rain.

Still, Glendening said that he was concerned about the low level in the Potomac and that he was asking residents statewide to shoulder the drought's burden by not watering lawns or flowers, taking shorter showers and not washing cars. He said mandatory restrictions would be decided in the coming days after a panel of state officials, headed by Department of the Environment Secretary Jane Nishida, reports to him on Tuesday.

Glendening said he would impose any mandatory restrictions on a statewide basis initially. But he has asked officials to consider whether any subsequent restrictions should be phased in on a regional basis based on local water supplies.

Any enforcement likely would be done with the help of local police departments, but Glendening said he hoped "most people will simply do the right thing."

This year's drought in Maryland is the second-worst since the government began keeping records in the 1880s. With rainfall as much as 50 percent below normal and the residual effects from the absence of rain last winter, Maryland has been among the hardest-hit drought areas in the nation.

The drought has shriveled corn, dropped rivers to record low levels, turned lawns rocklike and brown and prompted dozens of local jurisdictions to impose voluntary and, in some cases, mandatory water-use restrictions, banning car-washing and watering of lawns and gardens. Offenders are subject to fines.

Drought conditions also have hit Virginia, where it is "as dry as it's been since the 1930s, the Dust Bowl years," according to Al Peterlin, chief meteorologist with the U.S. Department of Agriculture. But he said nowhere in Virginia is faring as badly as Maryland.

Glendening's legal authority for the emergency declaration is the same used for disasters such as floods, blizzards and riots. It allowed him to seek federal aid for farmers whose crops have been devastated by the drought and to spend $3 million on state aid, which he said would be distributed "immediately."

Carroll County's Liberty Reservoir and two others serve 1.8 million people in the Baltimore region, including much of Howard and northern Anne Arundel counties. Unless there are serious water reductions or a significant rainfall, Glendening said, there is a 35-day water supply left at current consumption levels.

Howard County Public Works Director James M. Irvin said today that he had not been informed that the water supply was that low. The county receives water from Baltimore and the WSSC. "The last official word from them is everything's okay," he said.

Aides to Glendening said the 35-day estimate had been developed late Wednesday after experts reevaluated water supplies.

The governor said he was concerned about the low level of the Potomac, noting that its current flow was maintained only after being replenished for the first time ever by the Jennings Randolph Reservoir in Western Maryland.

But officials at the Interstate Commission on the Potomac River Basin said heavy rain this week actually allowed them to scale back the release of water from the reservoir into the river. About 2.2 billion gallons have been released from the 13.4 billion-gallon reservoir this month. The replenishment was not necessary for consumers but to protect river wildlife, officials said.

Rainfall in Montgomery and Prince George's counties has been nearly 14 inches below normal in the past year, ranking them among the counties facing the worse deficits in rain.

Montgomery County Executive Douglas M. Duncan (D) called for countywide voluntary water-use reductions July 12. Residents have been urged to curtail lawn sprinkling and to take shorter showers, and the county is not washing firetrucks and is postponing controlled burns for firefighter training.

In Poolesville, which has been particularly hard hit, there are mandatory water restrictions in place. Several communities in Allegany, Calvert, Carroll, Cecil, Frederick, Washington and Wicomico counties also have mandatory bans.

In Virginia, Loudoun became the first county in the region to impose mandatory restrictions on water use last week. Fairfax City has asked residents to cut back voluntarily. Fifteen counties have sought assistance from the office of Gov. James S. Gilmore III (R) in obtaining federal disaster aid for farmers because of the drought.

Even if normal rainfall was to resume, Maryland and Virginia would get little drought relief, forecasters say, because the summertime evaporation rate exceeds the rainfall rate. The only way the region could climb out of its rainfall deficit would be to have a rainy winter or to have a tropical storm dump huge quantities of water, which could mean dangerous flooding.

As for the immediate weather future, National Weather Service meteorologist Dewey Walston holds out little hope for relief, noting that the forecast for the next 10 days calls for "more of the same -- hot and dry."

Staff writers D'Vera Cohn, Ann O'Hanlon, Linda Perlstein, Fern Shen and Scott Wilson contributed to this report.

Saving Water

Here are the voluntary measures Gov. Parris N. Glendening is asking Marylanders to do to cut water consumption:

Don't water flowers or grass.

Don't wash cars.

Don't wash driveways or sidewalks.

Don't use water for ornamental fountains, waterfalls or reflecting pools.

Don't use dishwashers or washing machines unless fully loaded.

Don't water golf courses.

Don't fill or top off swimming pools.

Take shorter showers.

Repair leaky faucets.