It's better to use plastic bottles designed for reuse
2. Cleaning the bottles can cause a chemical leak
You'll notice I only recommend using lukewarm water to wash the bottles, with a strong emphasis on lukewarm. Using very hot water to clean the bottle (perhaps thinking to sterilize it), is a bad idea, especially if you're using single-use bottles. Experts believe that washing disposable bottles with hot water or in the dishwasher is a recipe for disaster, because the plastic they use to make these bottles is not made to withstand such heat. When it does heat up, there's a chance that dangerous chemicals will leak from the plastic and into the liquid inside the bottle.Reusable plastic bottles are made of tougher plastic, and are supposed to withstand higher temperatures without a problem. However, there is no safe way to completely remove all the dangers of using a plastic product for a long period of time. The best protection against chemical leaks is to drink your water from glass or stainless steel bottles. Even then, you'll need to wash and dry them properly, otherwise they too will become infested with bacteria.
3. Most of the bacteria in the bottle are found around the opening
Bacteria are mostly found near the opening of the bottle because our mouth itself contains bacteria, and also because of the way the cap is screwed on it, creating a perfect place for bacteria to thrive.
In a recent study, participants were instructed to drink from the same bottle for a week without washing it. At the end of the week, a small sample was taken from the opening of the bottle. What they found was disconcerting, to say the least. The bacteria found were the same kind that cause food poisoning, and in huge amounts.
If the participants in the study had continued to drink from the same bottle, they probably would have developed symptoms of nausea, diarrhea and even vomiting. The only way of preventing this kind of bacteria from flourishing in our bottles is to keep washing them properly. With disposable ones, however, I'd recommend keeping it that way and only use it once.
In any case, the cap of your bottle will always carry some bacteria, as it touches your hands as well. You can also drink from the bottle without touching it with your lips, letting the water flow right into your mouth.
Stainless steel bottles are preferable to plastic bottles
What's the bottom line? As mentioned, avoid using single-use bottles more than once. Throw them into the recycling bin or repurpose them yourself to something you can use. Even plastic bottles meant to be reused are not recommended and you'd be better off using stainless steel ones. Of course these must be regularly washed with lukewarm water and soap, just any other kitchen tool. Please share this information with as many people as you can. It's very healthy to drink a lot of water, but when it's filled with bacteria, you may do yourself more harm than good.
