Does bottled water "go bad" or grow bacteria after a few days after it!

Does bottled water "go bad" or grow bacteria after a few days after it's opened?

I've heard this before and sometimes reuse bottles while I'm at work, is it harmful to your health?

I'm no scientist, but it seems logical to think that your own bacteria from your mouth on the bottle could multiply over time. Especially at room temperatures. Whether it's harmful or not, I don't know. Possibly give you an upset stomach or at worst, if staph or strep were present, it could be something to consider. It doesn't take that long to put some baking soda and detergent into a bottle with hot water and shake hard, then rinse it out well and you're good to go again.