None, I stopped drinking bottle water sometime ago do to a few fears of the plastic and the fact it might not really be filtered correctly. I just use a filter for my own water and use an insulated bottle to hold it.
Yeah - luckily for me my office is right near one of those fancy water dispensing things so I use it often as an excuse to take five mins to just stand up and swig a glass down me. Think I've probably had 2ish litres today which isn't a bad haul on the old hydration front! Rather annoying though when I need to use the loo several times a day.