A school group from the Academy of the Pacific Rim Charter Public School in Hyde Park, Mass., checks into the Comfort Inn in Lorton. (Jeffrey MacMillan/JEFFREY MACMILLAN)

What does it take to accommodate hundreds of eighth-graders night after night?

If you ask Keith McNeill, the general manager of the Bethesda Marriott, the answer is early breakfasts, extra towels — and a lot of Dr. Pepper.

“I don’t know what it is, but we cannot restock the Dr. Pepper fast enough,” McNeill said, adding that he had just placed an emergency mid-week order. “It seems to be what all the kids are drinking these days — that, and Muscle Milk, Red Bull and Starbucks frappuccinos.”

Over the years, as eighth-grade trips to Washington have become a rite of passage for middle-schoolers around the country, McNeill’s staff has learned to anticipate the needs of the drove of students who come through the hotel every spring, summer and fall. For many, it is their first time traveling without their families.

“We stock the gift shop full of things they like to buy,” McNeill said. “One week its Cracker Jacks, and then it’s pita chips and hummus. They constantly keep us on our toes.”

For the host hotels — generally lower-priced properties on the outskirts of town — the annual trips are valuable sources of money, bringing in hundreds of thousands of dollars in revenue. This year, as government spending cuts continue to pelt the hospitality industry, hotel managers say eighth-grade trips have become more important than ever.

“In this time of government sequestration, can you imagine what would happen if we didn’t have school groups?” said Susan Sta. Cruz, general manager of the Comfort Inn in Lorton. “We probably wouldn’t survive.”

At the Sheraton Pentagon City, school groups account for 20,000 booked rooms in a typical year — adding up to about $250,000 in annual revenue, according to Rob Morgan, the hotel’s general manager.

Demand is so high during the spring that a 95-room building adjacent to the main hotel has been set aside almost exclusively for school trips. Rooms are outfitted with two queen-sized beds to accommodate four students at a time (save for a handful of single-bed rooms for chaperones). There no connecting doors between guest rooms.

“We get the occasional noise complaint here and there, but the vast majority of the kids are in bed by 10 or 10:30 [at night],” Morgan said. “For us, it’s very valuable business.”

Even as the groups bring in big money for host hotels, analysts say there isn’t much of a windfall for the broader Washington economy. The long-term plan, they say, is to entice students to return to the city one day as interns, young professionals and parents.

“An eighth-grader leaves the lightest economic footprint — they share hotel rooms, purchase cold drinks, a meal and maybe a T-shirt,” said Elliott Ferguson, chief executive of Destination D.C.

Since the recession, though, hotel owners say fewer school groups are coming through. Some have cancelled D.C. trips altogether, while others have done away with pricier activities such as shows at Ford’s Theatre.

“It’s gotten less busy over the years,” said Steve Nagar, general manager of the Holiday Inn Express in Largo. “Fewer groups are coming, but it’s still a big part of our business.”

Between March and June, about 80 of the 129 rooms at the Comfort Inn in Lorton are filled with eighth-graders. There are typically four students in each room — which translates to more than 300 students at the hotel on any given night between March and June.

“It’s pretty much back-to-back,” said Sta. Cruz, the general manager. “I can’t think of any hotel in the area that doesn’t want that kind of business.”

Preparations for students’ arrivals begin more than a year in advance, when schools and tour companies begin reserving blocks of rooms at area hotels. Before the groups arrive, hotels are asked to place four sets of towels in each bathroom instead of the standard two. Coffee machines are removed from guest rooms, and access to pay-per-view and long-distance phone calls are disabled.

“If the hotels can’t get it together and have everything ready to go, it becomes a real nightmare,” said Kathy Macwhinney, founder of K&K Tours in Celina, Ohio, which facilitates more than 50 school trips a year. “When you come in with a large group of students, it needs to run smoothly.”

To ensure students don’t sneak out at night, chaperones typically hold on to all room keys. The company also hires security guards to keep watch at night.

“You always have to be on the lookout,” Macwhinney said.

After a group of students were caught sending inappropriate photos through the Internet, Macwhinney began prohibiting students from bringing devices with Internet access.

“Kids just do not understand what’s okay and what’s not sometimes,” she said. “And a lot of them are traveling on their own for the first time.”

But mostly, tour guides and hotel managers said, students are too tired to get into much trouble. Students hit the road as early as 6 a.m., and often don’t return to the hotel until 9 or 10 at night.

“At first we thought it’d be like a sleepover,” said Diana Langenkamp, 14, who recently visited Washington from St. Henry, Ohio. “But at a sleepover, you hang out with your friends. At the hotel, we just showered as fast as we could and fell asleep.”