For thousands of Washington area high school seniors, June brings the annual tradition of Beach Week: a post-graduation blitz of sun, sand and, for many, drinking.

High schools counsel parents on how to keep their children safe. Police departments along the coast beef up their ranks and issue underage-drinking citations by the hundreds. And Maryland Attorney General Douglas F. Gansler, under fire for his appearance at a teenagers’ beach-house party, said last week that he should have assumed what has been obvious to so many: Teenagers drink during Beach Week.

Beach towns conduct YouTube and Twitter campaigns advertising alcohol-free events, fearing the damage and danger that can come during high school’s version of college spring break. Still, Sgt. Clifford Dempsey, a Dewey Beach police officer, said that during Beach Week, “it’s very, very rare we ever handle a party or disturbance complaint that doesn’t involve alcohol.”

The role of alcohol during the post-graduation celebration surfaced last week after published photos showed Gansler, a Democratic candidate for governor, amid a throng of teenagers at a June party in South Bethany, Del.

At a news conference Thursday after the first photo was published in the Baltimore Sun, Gansler said he “probably should have assumed there was drinking” and should have talked to the parent chaperon on duty.

Gansler declined media interviews Friday but fulfilled a previous commitment Saturday to appear on a WJFK-FM radio show.

“You have a bad day here, you have a good day there, but you know, this was a rough week, the character assassination and all that kind of stuff,” said Gansler, a former Montgomery County state’s attorney. “There are definitely people who don’t want me to become governor, and you have to sort of ask yourself why that would be.”

Gansler’s son was one of about a dozen new graduates of the Landon School in Bethesda who were staying in a six-bedroom rental home in South Bethany. Leading up to the week-long celebration, parents made extensive plans to monitor their children’s behavior and ensure that the house stayed clean. They also were clearly concerned about underage drinking and other safety issues.

E-mails obtained by The Washington Post, which included Gansler’s e-mail address at the attorney general’s office, had a chaperon schedule that listed two to four names for each night of the teens’ six-day stay. A “Doug” is listed as a parent chaperon for the first two nights — Saturday and Sunday. For Thursday night, the night of the party, the single name listed is not Gansler’s, and his spokesman said he did not fill any chaperon shifts.

A document titled “2013 Beach Week Rules — Final” listed 13 rules. They included a 1 a.m. curfew, no swimming after dark, no driving, no girls in bedrooms. Rule No. 7: “No hard liquor or controlled substances may be consumed.” The list said nothing about beer or wine.

One of the parents, who spoke on the condition of anonymity about the socially delicate situation, said the adults also duct-taped a back gate closed, monitored the single entrance, took away the boys’ car keys, checked for liquor and drugs, and sealed off a veranda to keep the noise down and prevent anyone from falling off.

“The whole goal was, ‘Don’t let these kids ruin the rest of their life by doing something extremely stupid,’ ” the parent said. “You try to control as much as you can — but be honest, these are 18-, 19-year-old kids.”

The parent said SUVs would pull up to the house and drop off teenage girls for the evening. Sometimes the boys went out, and sometimes they stayed at the house, where parents would cook big breakfasts and dinners, pick up pizza and wash dishes for the boys, the parent said.

Parents, including some who had beach houses nearby, were in and out, especially during the day.

“It was a lot of screening — kicking people out of bedrooms,” the parent said.

Some of the teens also appeared to have been drinking, the parent said.

“What amazed me the most was some of these kids I’ve known for years — how wild they could be — drunk drunk,” the parent said.

The legal drinking age in Delaware is 21. A first conviction for providing alcohol to a minor carries a fine of up to $100 and up to 30 days in jail, Dempsey said.

Eastern Shore police say Beach Week students, whom locals call “June bugs,” usually bring alcohol with them, noting that local bars and liquor store owners are well-versed in spotting fake IDs.

“If they’re coming, not every child is going to drink,” said Keith W. Banks, chief of the Rehoboth Beach Police Department. “But to sit there and say there won’t be beer is naive.”

Ocean City police spokesman Michael Levy said underage alcohol citations explode during Beach Week celebrations. In June 2012, Ocean City police cited 877 people for underage drinking, compared to 40 citations in May and 102 in July.

Patrick Wiley, a spokesman for the South Bethany Police Department, said the agency works closely with rental companies, local real estate agents and beach house owners to track the teens.

“We know who the June bugs are and where they’re at,” Wiley said. “We tell rental agencies: ‘Make sure you’re talking to your tenants and let them know what the laws are and not let things get out of hand.’ ”

Beach Week festivities aren’t sanctioned by school systems, and school officials say they worry.

Alan Goodwin, principal of Walt Whitman High School in Bethesda, said underage drinking at Beach Week is such a “huge concern” that school officials suggest alternatives to parents. Those include a post-graduation trip to Walt Disney World in Florida that a Whitman teacher usually hosts. and celebrating at beach houses outside the Beach Week areas so “they don’t have to worry about the boardwalk and drinking.”

Even so, Goodwin said, “Each year, we kind of hold our breath and hope that nothing goes wrong.”

Donna St. George, Lynh Bui and John Wagner contributed to this report.