I don't drink bottled water, because
- making plastic bottles uses a lot of fuel and water: it takes several times more water to make the bottle than to fill it!, and
- most bottled water is municipal water, but with less regulation for safety.
There are a few times when bottled water is appropriate (such as when local water is known to be unsafe), but generally it can be avoided for a more ecological choice. Consider a reusable water bottle and a water filter instead.