S.B.
When I first moved to a tiny town, no one warned me about the water.
I found out the hard way.
I put in a brand new white terry bathrobe and it came out looking like I'd drug it through every mud puddle within a 300 mile radius.
It was ruined and I was so upset!
Iron out was the only thing I found that worked halfway well.
Eventually, public works replaced the old pipes and the problem was solved, thank goodness.
My in-laws had a water softening system and never had that problem at all, but they had city water, so I'm wondering if the water softener is really the culprit.
I hope you get some great advice though, because I know how annoying it can be!