Take a black pot (very clean) fill it with water and let it get to a rolling
boil. Then turn it off and let it sit for awhile. Then see if anything
(grit) has settled in the bottom. If the grit is white then it would be
limestone. Which is what I just found out about the house we just bought. I
have county water and it was 19 grains of hardness with limestone deposits
in it, so far it has cost me 1900.00 to make my water clean and grit free.
We had to get a water softner and a carbon/charcoal filter.

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