My water comes out of the ground at 42 degrees f year round.
Must not be in southern Arizona, then. I don’t think even deep wells run that cool, much less piped water.
I put mixing valves in because my toilets would sweat gallons of water all over the floor in warm weather. Both hot and cold water fed the toilets.
A friend of ours pumps water from the bottom of the Chattahoochee River into the marble floors of his house in the summer for cooling. In winter they have a diversion valve that recorculates the water to solar collectors that heat his indoor swimming pool. It’s nice to be rich. Warm floors in the winter. Cool floors in the summer.