Everything in the dishwasher had white residue all over it.”
IF everything in the dishwasher had a residue- what will prevent this same residue from forming inside all your pipes taking water out of your house??
Likely nothing. I live in an area with very hard scale water. My water heater and pipes will likely be toast soon. I'm not so much worried about the residue on the 4" pipes leading out as I am the 1/2" pipes leading in.
It does - I lived most of my life in very hard water areas (till the last 5 years or so), and the hard water residue builds up especially on the heater coils in the hot water heater. Lots of people replace the whole water heater when they may be able to get by another 5 years with just replacing the elements.
Over time, though, it does coat everything. Dang low-flow faucets get down to just a trickle in a few years, so you know it's building up in the new smaller diameter water lines...