Be careful with bottled water, some is not as 'clean' as tap water.
Very true. Tap water has to be tested at every step of its processing, and it is tested for around 80 - 90 different substances.
Bottled 'mineral water' need only be tested for 13 chemicals and bacteria, and can be tested whenever it suits the 'manufacturer'. 'Spring water' is even less rigorous, and can be sold without any analysis being done at all. I saw some results of research done at Aberystwyth university on bottled water that I thought were pretty worrying.