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What Causes White Scale on Faucets?
By North DFW Water Editorial Team · Published 2025-01-01
Hardness minerals — calcium and magnesium — and the treatment that's actually designed to address them.
It's hardness, not contamination
The white residue on faucets, shower glass, and dishes is caused by dissolved calcium and magnesium — the minerals that make water "hard." Hardness is a mineral concern, not a contamination issue.
What softening does
A traditional ion-exchange water softener is the treatment designed specifically for hardness. Resin beads exchange hardness minerals for sodium (or potassium), and the resin is regenerated periodically using salt.
About 'salt-free' alternatives
Salt-free conditioning systems change how hardness minerals behave but do not remove them. They are not true softeners.
Editorial disclaimer: This article is general education. System recommendations should be based on your home's water source and conditions. Sources:
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