According to this table you need 2500 liters of water per 1 kg of rice: http://www.theguardian.com/news/datablog/2013/jan/10/how-much-water-food-production-was

According to this table you need 2500 liters of water per 1 kg of rice: http://www.theguardian.com/news/datablog/2013/jan/10/how-much-water-food-production-waste http://www.theguardian.com/news/datablog/2013/jan/10/how-muc... 25 gallons per serving seems to be underestimated.