How a Water Softener Works
A water softener is an appliance that is typically used in a residential environment to remove the hardness from the water being used for drinking, bathing, cooking, and washing clothes.
Hard water can cause visible scale to form on water-using appliances such as the dishwasher, washing machine, and iron. Homeowners with hard water and glasswork in their bathrooms are also faced with the prospect of almost daily cleaning. Hard water can also cause scale to form in some hidden places, such as the heating element of your hot water heater. Over time this can drastically reduce the efficiency of this device and cost homeowners money.
While prolonging the life and beauty of appliances is certainly one good reason to purchase a softener, many people with hard water choose a softener for other aesthetic reasons. Soft water creates softer skin, shinier hair, and cleaner laundry.
So how does a softener make water soft? To answer this question one has to understand what water hardness is. Hard water is simply water that contains calcium and magnesium compounds. The more calcium and magnesium the water contains, the harder it is. Calcium and magnesium are mainly found in bedrock. When it rains, water percolates through the ground and dissolves some of this rock. This is how calcium and magnesium end up in our water in the first place. Water that comes from wells is typically much harder than water that comes from lakes or rivers. In order to make water soft, the calcium and magnesium containing compounds need to be taken out. This is accomplished by a water softener, sometimes called a water conditioner.
A water softener is usually comprised of two tanks. One tank, called the mineral tank, contains softening resin. The other tank, called the brine tank, contains rock salt mixed with water. As water enters the home through the water main, it is pushed through the mineral tank, containing the resin. Resin looks like very small plastic beads. The resin contained in the mineral tank has an attraction to calcium and magnesium containing compounds. As the water flows past the resin any calcium and magnesium compounds will stick to the resin and will be removed from the water. In this process, the resin releases a sodium ion to the water. Because this trade occurs - calcium or magnesium for sodium - softener resin is known as ion exchange resin. The removal of the calcium and magnesium makes the water soft.
This process occurs for a few days, the resin exchanging its sodium ions for calcium or magnesium compounds. Eventually each tiny bead of resin becomes completely bound with calcium and magnesium and cannot remove any more from the water. At this point the softener goes through its regeneration cycle. Since regenerating a softener interrupts the flow of water to the home, this cycle is usually set to happen in the middle of the night. Valves inside of the softener controller allow the saltwater liquid from the brine tank to flood the resin tank. The sodium in the brine pushes the calcium and magnesium off the resin. They are then flushed down the drain. Now, all of the resin has been reloaded with sodium and is again ready to trade its sodium for more calcium or magnesium.
Homeowners simply have to make sure that they monitor the salt level in the brine tank and add a bag of salt when it is getting low. The water softener should take care of the rest.