Yea, we have to run CLR through the coffee machines regularly, use special cleaners in dishwasher, and cleaners in washing machine. It's time for a new hot water heater too. I'm interested on how the bottom looks.
Btw, how would that tap water work with an oatmeal stout, say at 50/50?
Undiluted, it is likely to be too alkaline for even a stout. No guess on how much dilution would be needed, but that happens to be what certain software is for!