If it works for the soda...

Slap a deposit on it and be done with it. It works well enough for pop and beer and all vendors of bottled water are already selling pop; why not just add the deposit to the bottled water and be done with the discussion?

Call for cap on bottled water use
Financial times

It was not so long ago that asking a waiter for bottled water in a US or British restaurant was considered pretentious.

Today bottled water is so prevalent - in offices, coffee shops, supermarkets, and homes - that a request for tap water is likely to cause more embarrassment.

Over the past decade, global consumption of bottled water has soared to 180bn litres a year, from 78bn litres a decade ago, according to Zenith International, consultants to the food and drinks industry. However, questions are now being asked about the environmental costs of packaging this volume of water in disposable plastic containers.

In the US, the world's biggest market for bottled water, city governments have started banning bottled water dispensers from their offices, with some switching to filtered water systems. About 40 per cent of bottled water sold in the US, including Aquafina and Dasani, is purified tap water.