When I lived in Ohio, our water had high iron content, leaving rusty deposits on my shower, sink, even clothes. Now, living in Florida, our water here is rich in limestone deposits (probably calcium too), which I find being worse than iron. After just a few uses, small limestone stains get accumulated on the shower glass door or curtain, and I even notice it on plates / glasses fresh from the dishwasher. What's the water like where you live?
I got quite a shock when I was living in the UK because the water had lime in it and everything ended up nasty. In NZ water is... water, sure it's got fluoride (in most places) and there must be some sort of chlorine to kill the bugs but we get no residues, there's nothing to worry about.