Nearly every week, Montgomery County officials send young workers into stores, restaurants and bars to see whether the establishment does what it is supposed to: tell the teens they cannot buy alcohol.

Nearly 20 percent of the time, the businesses violate the law prohibiting the sale of alcohol to people under age 21. When the county first started such checks in the early 1990s, the violation rate was about 50 percent.

"Montgomery County has one of most aggressive 'sales to minor' enforcements in the country," said Dennis Theoharis, executive director of the Montgomery County Office of the Board of License Enforcement. "We are one of the few jurisdictions that on a regular basis, at least weekly, are sending under-age-21 government employees to conduct compliance checks."

The license enforcement office and the county police conduct 300 such compliance checks each every year.

From March 2002 to February, the county issued 215 alcohol violations; of that number, 114 involved the sale of alcohol to minors. There are 867 businesses licensed to sell alcoholic beverages in the county, not counting the 24 county-owned liquor stores.

"We are finding in our compliance checks that the stores are not doing the math when checking the IDs," Theoharis said. "We are recommending that if you sell alcohol, you need an identification machine."

The Montgomery County Office of License Commissioners will provide monthly information to Montgomery Extra about businesses with alcohol violations. The first list appears today.