The brand's Still Spring Water with Chocolate is making its national debut now, rolling into Asda stores. It had previously only been available in some Co-op stores and selected cash and carries.
Flagged up on pack as a new flavour which is sugar-free, the chocolate water contains flavouring and sweeteners.
Spokesman Simon Russell said: "Our consumer research shows this is an offering which certainly polarises opinion, a bit like Marmite does.
"People either love it or hate it but everyone we spoke to said they knew someone who would like it."