Another data point: in a household of 2, we may consume 2-3 liters on peak days, probably an average of 1 a day during warm periods in the year. His math is probably right, but his assumptions don't seem to be backed by anything but anecdote! Also, saving bottles is a footnote, but I think environmental benefit adds up quickly when you compare the cost of transporting lots of bottles from the bottler to the store to your house to the recycling center. Wish he had some hard real-world usage data available.