If you want to get fancy, grab some old-fashioned washing soda (sodium carbonate) from the laundry aisle. Add a teaspoon to a glass of your water, stir, and watch. If the water turns milky or forms floating white curds, congratulations—you’ve got hard water.
It’s basically the same science: the washing soda grabs the calcium and magnesium and makes them visible as solid particles. It’s like the minerals are finally caught on camera after years of hiding in plain sight.
