Two supermarkets have denied claims the economy-price own-brand bottled water they sell is in fact tap water.
The allegations surrounded Tesco Everyday Value Still Water and Asda Smartprice Still Water, which reportedly sit on shelves alongside major mineral water brands such as Evian and Perrier.
The Daily Mail claimed the products were simply a filtered version of what is supplied to almost all domestic homes - but that there was no labelling on the bottles saying so.
It was likened to the fictional situation in the sitcom Only Fools And Horses where protagonists Del Boy and Rodney Trotter start selling "Peckham Spring", which is in fact water from the taps of their London council flat.
Both supermarkets denied misleading their customers in any way, saying the bottles gave customers a clear idea of what they were buying.
"Our Smart Price water is treated to remove chlorine, further filtered, then bottled," she said.
"If sparkling, carbon dioxide is added for a bit of fizz. The label on the bottle tells our customers just that.
"Our two-litre bottle is 17p. For comparison - if a customer bought a Brita water filter jug at £16 and used it for the recommended 40 gallons, it would cost 21p to produce two litres of filtered water.
"We're saving our customers time and money - as well as providing a container."
A spokeswoman for Tesco (LSE: TSCO.L - news) , whose Everyday Value Still Water also retails for 17p for two litres, said: "Our Everyday Value Still Water goes through a complex filtration process to improve the taste and remove impurities.
"Tesco sells a wide range of waters to suit all tastes and budgets. All of our products are clearly labelled so customers know what they are buying."