I try to find ways to minimize my carbon footprint. One way I do this is to not buy disposable waterbottles. They are made from petroleum, which is disasterous for the environment. They are made of PET which is harmful plastic. I can tell because it smells funny when I open it, and the water has a disgusting plastic taste if it is a few weeks old.
Having a reusable water bottle saves me money. I also have a britta pitcher; while it is also a plastic item, one plastic item with a one-time expense is much better than putting hundereds of bottles in the trash because where I live does not have a recycling program. I drink at least 80 oz of water per day; I love how it tastes, and I love knowing that no matter how long it is in my stainless steel klean kantine bottle that it will stay cold and not taste or smell awful when I drink.