Festival promoters provide space, equipment and marketing for the groups, which, along with beefed up security and medical personnel, help the festivals demonstrate accountability. Such concerns became more of a promoter’s imperative after a handful of festival tragedies led to waves of bad press, especially for electronic dance music, or E.D.M. In 2010, a 15-year-old girl died of a drug overdose after attending Electric Daisy Carnival in Los Angeles; there were two drug-related deaths at New York’s Electric Zoo in 2013; and two more stemming from Electric Daisy Carnival in Las Vegas the next year.

Tom Russell, a former Bonnaroo promoter who went on to start Founders Entertainment, which produces Governors Ball, acknowledged the need to find a space for tamer music fans. “A lot of promoters know that folks like to have a good time at festivals and they want to balance that with areas that promote a sober experience,” he said. “People are going to do what they want to do, but I want to create a safe environment.”

The sober music scene, which is not affiliated with any particular 12-step program, stems in large part from a group of Grateful Dead fans who banded together in the 1980s to avoid their old vices while still enjoying the music. Known as the Wharf Rats, after a Dead song about a down and out wino, they came to use yellow balloons as a beacon at concerts, a symbol that persists among sober groups today.

So-called yellow balloon communities proliferated among other jam bands — Phish has the Phellowship, Widespread Panic has the Gateway — and culminated unofficially at Bonnaroo, which started in 2002. By 2008, Bonnaroo’s promoters noticed the grassroots movement and gave Soberoo dedicated real estate, where volunteers staff an information table and now host three or four daily meetings throughout the weekend. Attendance at the scheduled gatherings can range from a handful of regulars to more than 150 people.

“The festivals certainly take advantage of the benefits we provide,” Mr. Whelan said. “We’re doing a good thing, bringing positive energy that all these festivals embrace. They sell tickets as a result of the goodwill.” He is now working to incorporate a 501(c)(3) nonprofit, called Harmonium, as an umbrella organization for the festival groups.