Lately it has come to light that it is very important to use safe water bottles, which most are not. Now, of course safety has degrees and we may be talking about relatively minor levels of poison in the long run, but especially in the case of babies this is an issue that must be taken seriously. I suspect that as time goes on our society will realize more and more things that we have created out of plastics, etc. have been subtly harming us.
Let's first take a look at the most common form of water bottle. This is the kind that all off-the-grocery-shelf bottled water comes in. It is not safe, by the way. Have you ever bought one of these in a gas station, supermarket, or elsewhere? It is also the kind that soda comes in.
The reason these water bottles aren't safe is because they're made of polyethylene terephthalate which is also known as PET. This plastic isn't necessarily harmful in and of itself, but over time it can break down and start leaching Bis(2-ethylhexyl)phthalate, or DEHP. This is where the problem is. DEHP is a probable carcinogen, which means that it probably leads to cancer.
So this can get into whatever you are drinking, especially if you re-use the bottle. (A lot of people save money by re-using their bottled water bottles in this manner.) Bacteria can breed in cracks in these bottles, too. Not very safe!
In my quest to learn about safe water bottles I also discovered that the kind that athletes use are not safe either. They are made of polycarbonate. Oh yeah, this is also what baby bottles are made out of. They leach a synthetic hormone called BPA.
I started to think that maybe there just aren't any safe water bottles. Then I learned about a slightly out of the box solution: stainless steel. This is the way to go if you really want to be safe from poisonous plastics and carcinogens. With a stainless steel water bottle there is no leaching at all. It is really the only good way to go that I have been able to discover to date. You can try aluminum but you have to be sure the maker is using some sort of a protective lining. I am glad I was able to find all of this out.