When we soften water using a water softener all it does is remove the calcium and magnesium minerals that are responsible for the limescale around your home.

This is done by a process called Ion exchange (please see How does a water softener work).

There are lots of urban myths and misunderstandings around how the water softening process works. But the fact is, a water softener does leave a minute trace of sodium in your softened water, which you cannot taste or smell. It is not detectable, and salt is not added to the water.

If the water hardness of your property, before softening, is under 400 PPM (which most of our local area is) the softened water is safe to drink and does not contain unhealthy levels of sodium – in the context of water quality, PPM, or parts per million, is a unit of measurement used for the concentration of dissolved substances (like minerals or contaminants) in water, with 1 PPM roughly equivalent to 1 milligram per litre (mg/L).

However if it does exceed 400 PPM a separate hard water tap for drinking is advised.

You should also be aware that it is not recommended to use softened water for making up baby formula, as it may affect its nutritional balance, or if you have been prescribed a low/zero sodium diet by your GP.

The average amount of sodium found in a 250ml glass of softened water contributes approximately 25mg or 1% of your daily sodium intake (Recommended daily sodium intake by the NHS is 6g). An average glass of milk contains 105-120mgs of sodium.