I wondered if my tap water had metals in it. A bottle of soap used to clean had water drops that eventually fell to the bottom. This is a plastic bottle, stone countertop...the water dried...then rusted.
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@scottyorange Most tap water has iron in it, and iron in those concentrations is safe and harmless unless perhaps you suffer from hemochromatosis.
@scottyorange When I lived out in rural Iowa, we'd sometime have massive rust come out of the water if we didn't condition it. The only problem we really had was it staining clothes.