Re: Hard water
We have super hard well water and I've never had rust stains on anything. I also use vinegar on my clothes with every wash as fabric softener, and I've never had a problem with odors, but maybe it is different with dirty diapers? I haven't washed dirty diapers yet.
We also had super hard city water at our last house, caused by iron (our shower would turn orange between cleanings), and I NEVER in 20 years of living on my own had rust stains on my clothing.