Water softener salt is designed for one job: regenerating the resin beads inside your softener. It’s usually made from evaporated salt, which is 99.9% pure sodium chloride. That’s it—no extra minerals, no dirt, no surprises.
Rock salt, on the other hand, is the wild child of the salt family. It’s mined directly from underground deposits and still contains insoluble impurities like clay, sand, and even trace amounts of heavy metals. Pretty cool for melting ice on your driveway, right? Not so cool for your expensive water softener.
Why does purity matter? Because those impurities in rock salt can build up like gunk in a drainpipe. They form a nasty sludge called "mush" that clogs your softener’s valve and turns your appliance into a paperweight. Your machine doesn’t want a gritty mud bath—it wants clean, dissolved salt water.
