The regional hosepipe ban has become an annual event almost as regular as Easter itself. But while millions of Britons all over southern England will be understandably peeved over being unable to water gardens and hose down patios over the coming weeks, it is important and timely to remind ourselves of the vast amount of water that's squandered every year on animal agriculture.

Around 90% of the world's total managed water supply is used to grow food. Most of this is completely wasted by irrigating land used to grow crops for livestock rather than food for direct consumption by humans. A staggering one-third of the world's total cereal crop and more than 90% of the world's soya crop is used for animal feed. The water that it takes to grow all that, plus what it takes to clean away the filth of factory farms, transport trucks and abattoirs, means that the livestock industry is placing a serious strain on our water supply, and not surprisingly, most of the water comes from the countries that have the least.

These revelations have led to an influential UN report naming the livestock sector "one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global". The 2006 report, Livestock's Long Shadow, highlighted freshwater scarcity among the many environmental problems and called the livestock sector "a key player in increasing water use" and "probably the largest sectoral source of water pollution."

It takes, on average, 15,500 litres of water to produce one kilogram of beef. To put this in context, that is the equivalent of 50 baths of water to produce one steak - 15 times more water than is needed to produce one kilogram of wheat. To produce the diet of a typical meat-eater takes the equivalent of 5,000 litres of water per day - more than enough to water your garden and the gardens of all your neighbours as well.

The aforementioned report concludes that the meat industry "should be a major policy focus when dealing with problems of land degradation, climate change and air pollution, water shortage and water pollution, and loss of biodiversity". And others have gone further than that.

A leading authority on climate change, Lord Stern, told The Times, "Meat is a wasteful use of water and creates a lot of greenhouse gases. It puts enormous pressure on the world's resources". He indicated that he favoured significantly higher prices for meat and other foods that contribute to climate change and concluded that "[a] vegetarian diet is better".

Similarly, in 2008, John Anthony Allan, a professor at King's College London and the winner of the prestigious Stockholm Water Prize, urged people worldwide to go vegetarian because of the tremendous waste of water involved in eating animals.

The most logical way for us to conserve water, land and other resources - and reduce animal suffering - is to kick our meat habit. We can save more water by not eating meat for just a few days than we can by not showering for an entire year. By going vegan, we'll be able to clean our cars and clear our consciences.

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