Recent reports from consultancy firm Zenith, International indicated UK consumption of all water drinks rose 8.2 percent in 2015 to 3,299 million liters (871.5 million gallons). Volumes have more than doubled over the past 15 years and consumption per person now stands at 51.7 liters (13.6 gallons) a year, with plain water at 44.1 liters (11.6 gallons) and water-plus at 7.6 liters. (2 gallons).