The water in the area I'm living in is pretty good and I never had problems because of it, it's clean, it doesn't need boiling and it never turned to any strange color. I drank it all my life and it has never been bad for me, so that's the water I give to my pets. None of my animals got sick because of the water I gave or give them.
As for the 'special water for pets', I would never buy it. I would prefer boiling the tap water or give them the water I buy for myself.