Do you drink bottled water because you think it is safer and/or easier? The environmental impact of drinking bottled water is substantially higher than tap water. To make one bottle of water it actual takes more than 6 times that same amount of water. That is just crazy. You also have to consider energy use, transportation, production of the plastic, waste and the overall emissions from the entire process. Now that doesn't mean that there are environmental impacts from tap water. That water is treated and uses energy but it is far less of an impact than bottled water.
If you have to drink bottled water make sure you either reuse the bottle several times or that you recycle it. Alternatively if you do not have to drink bottle water then switch to tap water. Get your self a cool water bottle and carry that with you. There are some really nice stainless steel water bottles available online or at any "outdoorsy" store.
Take the Think Outside the Bottle Pledge and reduce your overall carbon footprint.