Utah-based drink chain Swig coined “dirty soda” back in 2010. Fifteen years later, the trend is fueling innovation everywhere from PepsiCo to McDonald’s, infusing the sluggish beverage category with new life.

“Dirty soda” drinks use pop as a base, followed by flavored syrups, cream or other ingredients. While Swig claims credit — and the trademark — for dirty soda, TikTok videos and the reality TV show “The Secret Lives of Mormon Wives” have helped the trend spread far and wide, outpacing even the soda chain’s speedy expansion.

Now, consumers can find it nearly everywhere, from grocery store aisles to fast-food chains.

In a few weeks, Pepsi plans to unveil two ready-to-drink dirty soda-inspired beverages at the National Association of Convenience Stores trade show in Chicago. The new drinks, the Dirty Dew and the Mug Floats Vanilla Howler, follow on the heels of the Pepsi Wild Cherry & Cream flavor, which hit shelves earlier this year.

“I think it’s a great opportunity for people like us, like PepsiCo, and for consumers to experience soda in a new way — and in some ways, an old way,” Pepsi Beverages North America Chief Marketing Officer Mark Kirkham told CNBC, comparing the rise of dirty soda to root beer floats and the soda shops of yore.

Dirty soda has also drawn new interest beyond beverage players. According to Datassential, 2.7% of U.S. eateries offer a carbonated soft drink that includes cream or milk, up from 1.5% a decade ago.

Newcomers to the trend include TGI Fridays, which launched dirty soda as a limited-time menu item this summer that could be spiked with alcohol. McDonald’s is testing flavored sodas, like a “Sprite Lunar Splash,” at more than 500 locations after winding down its drinks-focused spinoff CosMc’s in June. Yum Brands’ Taco Bell has also been offering limited-time menu items, like a dirty Mountain Dew Baja Blast.

As Swig has grown, so have the number of chains looking to emulate its success. Rival soda shops like Sodalicious, Fiiz and Cool Sips are also benefiting from the trend. Coffee shops, like Dutch Bros., have also added it to their menus. And now fast-food chains are hopping on the bandwagon.

“It validates that this is a category, and McDonald’s and Taco Bell wouldn’t be getting into it if it wasn’t something that had broad appeal that they could sell everywhere, in thousands of locations,” Dunn said. “It’s kind of flattering that we created a category that now everybody is copying.”

For restaurants, adding dirty soda to the menu is easier than it might sound.

“It’s a custom drink offering that, one, allows the brands to leverage something that they already have right there: their soda machine,” said Erica Holland-Toll, culinary director at The Culinary Edge, which advises restaurants on food and beverage innovation. “Two, it incorporates either a one-touch ingredient, or if they’re already open for breakfast, it’s quite likely that they’ve got a creamer in house.”

On the other hand, offering customizable coffee drinks is usually much more difficult — which has contributed to the struggles at Starbucks.

“The espresso world — that’s so much more complicated,” Holland-Toll said.

Dirty soda also has wide appeal. With less caffeine than coffee, consumers can drink it all day long. Plus, it’s “much more accessible” than some coffee house trends, like an espresso tonic, according to Holland-Toll. The bright colors of many dirty sodas also make them more attractive to consumers, who were likely introduced to the trend via a TikTok video.

But perhaps above all, dirty soda can help restaurants draw in customers who are otherwise feeling thrifty.

“It’s an affordable fun treat. You’re not going out and spending $30 or $50, right?” said Sally Lyons Watt, chief advisor of consumer goods and foodservice insights for Circana. “It’s something that people can walk away saying, ‘Wow, that was yummy’ or ‘I feel better because I just had that.'”

“For us, it serves as a recruitment tool, bringing new users into the trademark,” said Katie Webb, vice president of innovation and transformation for Keurig Dr Pepper. “It really draws them all the way back to the base brand, which ends up being extremely impact for us long after.”

And just as craft cocktail culture led to the rise of canned cocktails, the popularity of dirty soda is leading beverage giants to cash in with ready-to-drink versions that capitalize on the trend. Dr Pepper Creamy Coconut was the company’s most successful limited-time carbonated soft drink to date, based on retail dollar sales, according to Webb. And Kirkham said Pepsi Wild Cherry & Cream has been one of the fastest-growing flavor segments for the company.

“Some trends start retail and move over to foodservice,” Circana’s Lyons Wyatt said. “This one was a foodservice trend moving into retail.”

With Pepsi Wild Cherry & Cream and next year’s launch of Dirty Dew and the Mug Floats Vanilla Howler, Kirkham expects that consumers will become even more creative with their concoctions.

“I think it’s actually giving [consumers] the chance to experiment even more and customize more,” he said. “Now you have a brand new base.”