Hard water refers to mineral content/EC/PPM, not the PH.
Not only do you have to worry about PH, or at least pay attention to it, if your TAP water is anything over .5EC standard nutrient dosings are going to burn the absolute fuck out of your plant.
Do you have water spots on your chrome fixtures? You need to start out quarter strength or less. You can always add nutrients. Trust me, you don't want to be in a situation where you need to remove them.
To be a grower that's worth a damn (and doesn't just use experience/luck and goes around screaming "YOU DONT NEED NO PH/EC METER MORON" *Straw in mouth*) you need to buy a god damn PH/EC meter. I use an Apera PC60. Not the PH60.
Don't be a fucking redneck. Be intelligent.