The move is part of a realignment of the drinks company's brands that will see BBH handle fruits and carbonates, with CHI working on water variants, including Drench, and any new product developments.
CHI recently created an ad for the brand featuring Brains from Thunderbirds dancing to the classic 90s dance track Rhythm is a Dancer.
It is understood that Britvic is planning another UK water launch, to appear before the end of the year.
Simon Stewart, the marketing director at Britvic, said: "We believe both agencies will gain from this consolidation, with BBH bringing a new focus to our core brands and CHI launching our NPDs."
Tango, one of the all-time iconic advertisers, moved to CHI in 2002 from HHCL, which had handled the account for more than a decade.
The agency's famous work for the brand, which included ads such as Blackcurrant Tango's "St George" and spawned the line "You know when you've been Tango'd", saw sales of the drink soar in the early 90s to overtake rivals such as Lilt, Sunkist and Fanta.
However, as sales fell in the late 90s and early 2000s, the decision was taken to move the business into CHI. The agency then created the "fruit hit" campaign that saw people performing Jackass-style stunts with vast amounts of fruit.
The last Tango work from CHI appeared in 2006 and was a viral spoof of Sony "balls", in which fruit was fired down a hilly street in England.
The realignment also sees J2O moving back to BBH after the account was shifted into CHI in January 2006.
BBH originally picked up the business in 2004, after a reshuffle saw Barrett Cernis axed from the roster and Britvic's fruit and carbonates account split between BBH and CHI.
Britvic has seen good recent growth in its stills categories, including water, but less success with its carbonates.
In April, it announced a pre-tax profit of 13.2 per cent to £17.2 million for the 13 weeks to 13 April. Revenue on its still brands was up 2.8 per cent to £161.8 million, while revenue for carbonates increased by 0.4 per cent to £185.4 million.