Whenever I visit Hangzhou with travelers, we take an hour or two to spend at the tea farm, learning about the picking, drying and packaging process. More importantly, the local people educate us on the health benefits of green tea. Of course, we westerners understand that green tea is good for us, but for many Chinese, green tea really is the "apple a day."
The water in China is not potable. Not even the local people drink it. They are not all buying bottled water; they are boiling their water. Since green tea is good for their health, many Chinese people can be seen toting around a bottle or thermos of green tea, oftentimes lukewarm. This is their "Camelback," but it's filled with tea, not water.