Water that is high in salt is definitely bad for most plants. Many orchids are ph sensitive but ph can easily be adjusted. Is this what you mean?
Leafmite
There are many commercial vanda growers here in south Florida. They use our very hard local water on all their plants. It's so hard that it leaves a white residue on the leaves. Never use water from a water softener on orchids because it contains too much sodium. Other than that I think just about any water is fine.