Boil a cup of water in a clean pan until half of it evaporates. If you see a white, chalky film left behind on the bottom, that’s your hard water’s calling card. It’s like the mineral equivalent of a cat walking across your clean counter—only less furry and more annoying.
4 ways to measure water hardness _ how to check water hardness – PBFF
Fun fact: that white crust is actually calcium carbonate, the same stuff that makes up limestone caves and Tums antacid tablets. So in a weird way, your kettle is secretly growing cave formations for breakfast.
