HotRod wrote:
You need to tell us more about your setup..

1) What type of pipes are in the house?
2) What type of water are you on?

If you want to test the water take a white plastic bucket and pout some
water in it and let it site for a few days, did it dis-colour the bucket?

I am assuming metal. I just purchased the house a month or so ago. It
is about 24 years old. I am on city water. I will try your experiment
and see what I get.