Cloud Juice - or rainwater - is sampled in London's Claridges Hotel, one of more than 30 waters from the water menu.
Can experts tell London tap from the most expensive bottled water?
Nobody spotted the tap water, in fact one expert mistook it for the most expensive.
The UN says access to clean water is a human right but over a billion people round the world don't have access to safe drinking water.
There's enough oil used in the production process of water bottles in the UK to keep 17,000 cars on the road for a year.
Bottled water takes a lot of energy: being transported to us and the plastic or glass bottles that often end up in landfill.
The rising tide of plastic on the Dorset coastline - the amount of plastic produced globally has doubled since 2000.
There's also the hidden threat of granular pellets, the raw material that makes most plastic products.
Plastic is one of the reasons that the population of Fulmars has decreased since the mid 90s. If they don't choke on the raw plastic the toxins kill them.
At Defra they've ditched bottled water and drink from the bountiful tap.