Okay, hear us out before you start calling this list ridiculous. We swear it's true that consuming bottled water can be extremely harmful if the plastic contains BPA. BPA is a chemical that has been found to be harmful to humans, and unfortunately it lurks in so much of our plastic bottles and packaging, including reusable bottles and containers. As it mimics hormones, the problems associated with BPA have been early puberty, sperm reduction, and increased chances of contracting reproductive cancers. Some studies are even linking BPA to the growth of male breasts.
To avoid this chemical, buy a reusable BPA-free bottle and carry your water in that. Some commercial bottled water is now being sold in glass bottles, which are also safe. Whatever you do, make sure anything plastic states that it's BPA-free before you buy it.