Opting for spring water or mineral water

The best solution is to drink tap water! (It's the most ecologic and doesn't entail the waste of plastic bottles).
If not, then go for spring water, which is the most like tap water in terms of it's mineral content.
Also, the production of spring water is much more stricter than for mineral water which is often full of minerals, which if consumed in great quantities may be harmful.
It is also advised to regularly change the type of water you drink.