Coke has selected Lowe, which handles Sprite, to work on both projects.
The brand in research is believed to have had at least three working titles so far, and is currently referred to as Bon Aqua.
This is also the name of Coca-Cola's bottled water brand in Germany, Russia, Spain and France. However, Bon Aqua has not been confirmed as the name of a UK drink and no launch date has been set.
The company is researching whether project Bon Aqua should carry Coca-Cola branding. Coke's US water brand Dasani carries the wording 'From the Coca-Cola Company'.
Separately, Malvern will be repackaged and repositioned with a substantial marketing campaign later this year in an attempt to make it more of a consumer-orientated brand. It has only a fraction of the market and is served almost exclusively at conferences and in hotels.
Evian is the UK's market leader in still water, with 24.8% of value sales, followed by Volvic with 11.9% and Danone Activ with 5.7%.
The £770m market is ripe for further growth. According to Danone's Bottled Water Report 2002, just under two-thirds of the UK population drinks bottled water.
Water contributed 31% to the growth of the soft drink sector last year. This figure is expected to increase to 38% by 2004.
A spokesman for Coca-Cola confirmed that the company was "very active in the water category", but would not give further details.
Lowe was unavailable for comment.
Dasani is Coke's biggest water brand, but it also sells Mount Franklin and Pump in Australia and the Turkuaz brand in Turkey.
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