Health freaks, dissatisfied with tap water or commercially produced spring water, have taken to drinking water straight from the source.
'Raw water' is, as the name suggests, unfiltered, untreated, natural water bottled straight from the spring.
And there are American companies selling it for up to $6 (£4.40) a gallon, reports The Guardian .
It contains algae, microbes, minerals and beneficial probiotic bacteria - the stuff water processing removes.
Apparently it has a better mouthfeel and a fresher taste too.
But there's also a pretty good chance it contains animal faeces, harmful bacteria and viruses.
As a result, drinking untreated H20 can give you a number of unpleasant stomach and intestinal bugs including 'beaver fever', aka giardiasis which has symptoms including diarrhoea, abdominal pain and weight loss.
It's worth noting that man has known of the dangers of drinking untreated since prehistory.
In Northern Europe man brewed a low alcohol ale (also called 'small beer') for quenching thirsts; the brewing processes killed the nasties present in untreated water.
And in the eastern hemisphere - such as in China - water was boiled before consumption killing off harmful bacteria in the water.