My grandfather was in the "water" business for 50 years before handing the company off to my uncle.....
I personally don't drink hard water. Period. I can't even stand showering in it, and that's my biggest complaint with apartment living, actually. haha. I don't do bottled water, but I am a big fan of my reverse osmosis tap. The ones that you can get at home depot and the like for around $300 are kind of a rip off. They are tough on the electric bill, and not really made to last, and require regular maintenance. Same can be said for the water softeners you can get at places like that. Entire waste of money. My RO system was pricey, but I feel that it will pay off in the long run. We no longer have to buy bottled water, it requires very little cheap maintenance, and I noticed ZERO difference on my bills. If you have a GOOD water softener (not a big box home improvement store one) then your tap water should be absolutely fine for dogs and humans alike.
My dogs drink RO, but I don't worry about them drinking tap water at daycare or anything. They're dogs. They can eat rotting carcasses off the side of the road. *shrug* Just not something I worry about.