Montgomery County should keep its multimillion dollar monopoly on liquor sales, a task force appointed by the County Council recommended yesterday. But it said the Department of Liquor Control should avoid advertising campaigns that might prompt people to drink.

The 24-member task force, including members such as county finance department head Albert Gault and state delegate Idamae Garrott, said that the DLC should function "substantially in its present form" and the county's monopoly should continue to avoid "the proliferation of retail outlets."

Montgomery County is the only county in the country to control liquor sales within its borders. The task force said maintaining the monopoly would enhance the county's already sizeable tax base. Net sales for the DLC reached more than $74 million in 1981, according to DLC statistics.

"It was perceived that a change to private operation could result in an increase in the social problems of alcohol abuse, an already alarming county problem," the task force concluded.

The once obscure department made headlines in 1980 with news stories about possible favoritism to some distillers and questionable personnel assignments.

Because of the "only marginal public understanding" of the DLC, the task force recommended a public information program that would also publicize the human costs of alcohol abuse.