Water contains minerals depending on which location it has been collected from. However obtaining 'demineralised water' or 'distilled water' can actually cut down on your intake of these essential minerals.
If it is a taste issue then you can try different brands. Tap water can be improved in taste by the addition of in line filtration devices.
So is it tap or bottle water that you have a problem with?
In what way is your stomach upset?
Distilled water is demineralised so if you did not like the taste then it may be that it is not the minerals that is causing your dislike of taste.
How do you get on with fruit flavoured water?
If the water comes up in a spring from the ground then it absorbs minerals from the ground it passs through.
Silvercreek bottling company does a range of water: here or larger supplies: here