How Water Softeners Work

Many of our visitors usk us how water softeners work and why they should buy one. Below is a brief description.

Why buy a Water Softener?

Water softeners reduce the ‘hardness’ of normal mains water. Hard, unsoftened water contains more calcium and magnesium than normal soft water. This results in ‘scale’ being deposited on household goods like kettles, taps and washing machines. Hard water can drastically reduce the serviceable life of all water based products. Softened water also saves you money because you do not have to use so much washing powder, you do not have to add salt to your dishwasher and you don’t even need to use as much shampoo.

Another reason is your body. Many people find that washing and showering in hard water makes their skin dry. Installing a water softener will eliminate many dry skin problems associated with water.

Lastly water softeners are better than ‘scale reducers’ and other products because they actually remove the water hardening agents and flush them down the drain. Scale reducers only reduce the particle size in the hope that they do not cling to your plumbing components.

How does a Water Softener Work?

Watch this video to find out how water softeners work. Then read our description below.

As we have said a water softener works by removing calcium and magnesium deposits from your water supply thus reducing it’s hardness. How does it perform this function? There are four main components that make this operation possible. The first is the brine chamber. This holds salt blocks for use in the water softener. The second is the resin chamber which is often situated in the brine chamber and is filled with resin beads that are naturally negatively charged. The third is the motorised valve that diverts water to the different components in the water softener during operation using either a cam type valve or a disk valve. Essentially both valves perform the same function – to open and close inlets and outlets in a certain sequence as required by the water softener during ‘regeneration’. The forth is the control box which monitors water usage and most importantly the flow out of the resin chamber to the taps.

In normal operation the unsoftened water passes through the brine chamber, is softened,  and then runs off to your taps. The softening process occurs when hardened water, with naturally positively charged magnesium (M) and calcium (C) ions, passes through the resin chamber. The positive M and C ions attract to the negatively charged resin beads and do not continue on to your taps. This process continues as you use the softened water.

Water Softener Regeneration

Over time the resin beads get full of attracted M and C ions. The central control unit is constantly monitoring the resin chamber’s flow. When it notices a slowing in the water flow due to the large amount of M and C ions it activates the motorised valve. Firstly the valve allows water into the brine chamber to create a brine solution. This solution is then passed into the resin chamber to wash the M and C ions away and out of the discharge pipe, down the drain.

Some water softeners ‘learn’ when you use the most amount of water. This allows them to delay regeneration until the middle of the night. Other water softeners use the water pressure itself to drive the motorised valve instead of electricity, eradicating the need for a power supply.

How to install a Water Softener

It is a common misconseption that softened water is infact salt water. This is understandable as there is a brine chamber present. Infact the sodium content in a glass of softened water is equivalent to that of a glass of milk. Nevertheless to some softened water has a repugnant taste and it is not advised by health professionals to be a source of drinking water. That is why when installing a water softener most will leave the kitchen or drinks tap unsoftened. Also any outside taps are generally left unsoftened.


Most water softeners will be installed under the kitchen sink or as near to the incoming main as possible. After the unsoftened water outlet comes the water softener inlet valve. The bypass valve is present should the water softener need servicing without disrupting a water supply to the house. Some engineers install a filter on the inlets and outlets but that is up to manufacturer’s specification.

Where to buy a water softener

Water softeners are widely available online. Nowadays they can be installed by householders with a general knowledge of plumbing, reading the instructions and using this website for general reference. Install the product according to the manufacturer’s recommendations to avoid any warranty issues.

Even if you are using a qualified engineer to install the water softener, it is often more cost effective to buy the product yourself. You will avoid the engineer’s mark-up and know what you are getting. If you aren’t sure which water softener to buy, ask your installing engineer and they should be happy to inform you.