10 April 2018

How does a water softener work?

Some homeowners may ask, “What does a water softener do?” Simply put, they transform hard water into soft water. Here’s how.

Water softeners contain two separate chambers: a brine tank and a resin tank.  The resin tank is where the water softening takes place.

Water softeners make use of a process called ion exchange to remove the hardness ions from the water.  These hardness ions are primarily calcium and magnesium. The water softener resin tank contains a bed of small beads that have sodium ions electrostatically attached to them. The water softener pumps hard water through this resin bed and the hardness ions are exchanged with the sodium ions.  That is, the hardness ions will stick to the resin and displace the sodium ions which then end up in the softened water. 

Over time the resin fills up with hardness ions and can no longer soften the water. At that point the water softener must regenerate.  Salt brine from the brine tank is pumped into the resin and that salt brine washes away the hardness ions and replaces them with a fresh layer of sodium ions.  The softener resumes softening more water.

To learn more, check out our video.