A D.C. City Council proposal to raise the District's minimum age for drinking beer and wine to 21 was endorsed at a council hearing yesterday by several safe-driving advocates and Georgetown groups, but drew opposition from student leaders and a major alcoholic beverage association.

"The number of bar stools in Georgetown is approaching the number of residents," William A. Cochran, an Advisory Neighborhood Commission chairman, charged at the hearing.

"Can our community survive if we become a watering hole for under-age kids from surrounding jurisdictions?"

Michael Maher, executive director of the Washington, D.C., Restaurant and Beverage Association, countered by describing the Georgetown groups' arguments as "elitist" and warning that the city would risk losing nearly $6 million a year in sales taxes if the drinking age is raised.

The District recently has faced mounting pressure from Maryland, Virginia and federal officials to increase its minimum age. The city permits 18-year-olds to buy beer and wine, but restricts liquor sales to those 21 and older.

Congress last year moved to prod states to raise their drinking ages to 21 by threatening to cut federal highway aid. If the District fails to increase its minimum age to 21, officials said, it would face a loss of $2.5 million in highway funds in 1987 and $5 million the next year under the measure.

Mayor Marion Barry has not taken a stand on the issue. At yesterday's hearing, Gladys W. Mack, a top mayoral aide, testified that the threatened cut in highway aid "has to be considered," but she urged the council not to base any decision "solely on the monetary impact."

The Maryland General Assembly passed legislation three years ago to raise the state's drinking age for beer and wine to 21. In Virginia, the General Assembly voted earlier this year to increase the minimum age for drinking beer to 20 in 1986 and 21 in 1987.

The bill to raise the District's minimum age, sponsored by City Council member John A. Wilson (D-Ward 2), is considered unlikely to be adopted this year, according to city officials.

"What are we going to gain by changing the drinking age?" asked council member John Ray, who presided at yesterday's hearing. He cited a series of D.C. police statistics to show that people younger than 21 are involved in relatively few drunk driving incidents.

"I worry more about those over 21," Ray said.

Charles Hurley, a National Safety Council official, supported the bill, arguing that "a uniform drinking age can save lives."

"In the Washington metropolitan area, 23 percent of alcohol-related fatalities were caused by drivers under age 21 in 1984, up 18 percent over 1983," said Gary P. Smith, a Government Employees Insurance Co. official.

Georgetown groups cited a petition that they said was signed by owners of 76 Georgetown restaurants and bars supporting the proposal.

Paul Strauss, executive director of the D.C. Student Association, which represents college and university students, opposed the bill, describing it as discriminatory and unenforceable.