One huge barrier to this is the overabundance of them. People are often willing if not eager to spend a little extra for convenience. Prior to the saturation of bottled water, people would have to bring their own bottle if they wanted to bring water with them somewhere, or get it at their destination. Now it's so easy to throw a little bottle in their bag then throw it away when they're done. There's a strong emphasis on drinking plenty of water and its an easy "healthy habit" that many can adopt. At the same time, retailers display huge packs of single-portion water bottles at very affordable prices and this habit is even more convenient. The increase in public fill-stations is a step in the right direction, but more needs to be done to discourage the single serve, single use bottles. I've set myself us for success by having plenty of bottles available to me and by establishing the habit of filling them before I leave the house. I teach my kids to do the same so that they don't develop the habit of using disposable water bottles.