How much water does it use?
This depends on a number of factors, including the rock mechanics, the length of the horizontal part of the well and how many "frack stages" are planned. For a long lateral, with 45 stages, it might use between 18,000 and 27,000 cubic meters of water - or the equivalent of between 7 and 10 Olympic-sized swimming pools.
That initially sounds like a lot, but when you compare it to other existing uses of water, you soon find that it's very minor. For instance, on average, every person in the UK uses 150 litres of water a day - that's over 9 million cubic metres of water every single day, or over 3 billion cubic metres a year - you could frack between 130,000 and 200,000 wells with that!
A 2006 report by the Waste and Resources Action Programme (WRAP) found that UK manufacturing uses a staggering 414 million cubic metres of water a year, with the accommodation and food services sector using 134 million cubic metres a year.
Put into proper context, fracking for shale gas is not a big water user.