It seems likely that the people who consume most bottled water will be people who have the most disposable income and are the least likely to be frugal. Therefore, I would predict that the people who consume the greatest amount of bottled water would be relatively well-off people who are fairly young. Young people are less likely to be frugal and well-off people are more likely to have disposable income.
It could also be that the people who consume the most bottled water will be the people who have the most hectic lives. Therefore, I might also predict that people with 2 or more school-aged children will consume more bottled water. This will be the case because they are more hurried as they rush around getting their children to various activities. This will be particularly true if both parents have full-time jobs.