Just to clarify one thing; there is no nationwide ban on phosphates in dishwasher or laundry detergents, just an agreement by the big manufacturers not to use them. This is why Bubble Bandit can legally sell phosphated detergents. Some states do have bans, and they don’t ship to those places.
To find out your water hardness, call your local water utility. It might take awhile to get to someone who can answer the question — the receptionist won’t know. I eventually got to someone at the pumping plant who was happy to talk to me. He probably didn’t have much to do!