How Softener Works

Most water softeners on the market are ion exchange systems. In these systems, hardness ions (calcium and magnesium) are exchanged for salt (sodium or potassium) ions. The exchange takes place within the resin tank of the water softener. When water flows through the tank it comes in contact with small resin beads that are covered with salt ions. As water flows through the resin beads, hardness ions trade places with salt ions, hence the higher salt content in softened water.

As larger volumes of water are softened, the beads become exhausted and contain nothing but hardness ions . The beads are recharged by adding bags of salt to the brine tank. Recharging works the same as softening but in reverse. The hardness ions swap places with the salt ions in the brine tank and excess minerals are rinsed into the wastewater drain.

Demand initiated regeneration (DIR) water softeners are the most common ion exchange softeners sold locally. DIR softeners meter water usage over time and only regenerate when needed. Some softeners operate on a timer or schedule that regenerates at set increments. This older technology can be very wasteful of both salt and water because the softener will regenerate even during periods of low household water use (e.g. vacation away from home). At the same time, these models can leave you short of soft water if you have periods of higher water use (e.g. house guests).