I am not sure, but I think the white crust is Calcium of some kind that is dried all over the stainless steel. The same crap that creates the “bathtub ring” at Hoover Dam as the canyon walls are extremely steep near the dam, and the water level is very low.
This is why I never drink the tap water here! The water is fine for showering and washing clothes, but never drink the Colorado River water. The water smells like chlorine added by the city anyway, just as it did when I lived in Dunedin, Florida during the 1990s.
I have tried the filtres that screw onto the kitchen tap, they never seem to last and don’t taste as good as the costly bottled water, hence I buy the expensive bottled water. In my defense, the bottled water is far more portable, and my bottom two drawers in the refrigerator are always stocked with super cold, delicious water always ready to go!
Black and white on top, grayscale below.