Bottled water just doesn't add up. 'It struck me that all you had to do is take the water out of the ground and then sell it for more than the price of wine, milk or, for that matter, oil,' an ex-CEO of Perrier once said, providing a rather revealing industry snapshot. It takes 1.6 litres of water to produce every litre you buy. Celebrities like Paris Hilton give bottled water to their dogs (she buys a brand called Bling h2O at $550 a case), yet 1bn people worldwide don't have access to safe or clean water at all. That's why this summer you should favour bottles that 'give something back'. Frank Water (www.frankwater.com) funds 200 litres of clean water in the developing world for every litre it sells, and One (www.onedifference.org/uk/water/) and Belu (www.belu.org) use all their profits to pay for clean-water schemes. However, because the single-use plastic water bottle now accounts for 500,000 tonnes of non-biodegradable rubbish per year in the UK, the real ethical summer drink is good old tap water in a 'sustainable receptacle' - Woody Harrelson carries his in a glass jar. This is a pretty heavy option, but as single- use bottles may leach a chemical that disrupts your hormone cycle, search for containers such as flasks made from less harmful plastics like HDPE, LDPE, polypropylene and polyethylene. Plastics aren't always stated on the labels, so unless your container says otherwise, assume the worst and research alternatives online. If you don't mind people thinking you're about to undergo a blood transfusion, Platypus makes reusable and lightweight polyethylene hydration packs or go for a Nalgene or Sigg bottle. Better still, support the communal approach, stopping to drink from any remaining drinking fountains. They are one of the last (diminishing) symbols of sustainable H2O.