It is easy to think water that comes out of the tap is pretty much the same across the country, but this is often far from the case.

Whilst rainwater starts as very soft, water often travels a long distance before it reaches your tap, and will pick up dissolved minerals along the way, such as magnesium and especially calcium.

This is measured in parts per million (ppm), with any figure oper 200ppm seen as hard water, whilst anything below it is varying degrees of soft water.

In the UK in particular, there is a strong divide between the northwest and southeast with regards to hard and soft water. Manchester has the softest water, going as low as 25ppm in some places, whilst London has some of the hardest water in the country.

The reason for this is geographical; the south-east of England has a lot of chalk and limestone, which contain calcium and magnesium that is absorbed by the water.

On the other hand, the north-west is a granite region so fewer minerals are absorbed by the water as it makes its way to rivers and reservoirs.

Hard water can offer health benefits because of how much calcium is in it, but it can also calcify and cause buildups on your taps and showers, which may cause problems for your water system.

One way around this is using an ionised water filter to separate the water from the mineral deposits, leaving water at your optimum pH.

Along with this, water softening tablets exist and can be used to reduce the hardness of water, particularly in hot water tanks, showers, kettles and washing machines where limescale can cause problems.