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Hard Water Areas In The UK

Updated: Aug 25

You’ve probably heard the words ‘hard water’ and ‘soft water’ many times before and weren’t sure exactly what they meant. After all, they’re both liquid and if you jump too fast into a swimming pool, the water bruises your legs just the same. So, how can water be hard or soft?

The answer to the question refers to the concentration of dissolved minerals in the local water.

Limestone rocks
Areas with high concentration of Limestone tend to have hard water deposits

So, What is Hard Water?

Let’s think this through using the rain cycle as an example.


Water falls as rain from the clouds to the earth. This water has no dissolved minerals, so scientists classify it as ‘soft’. It lands on the ground and percolates through the soil and underlying rocks. If the rocks are permeable like limestone or chalk, the water will collect mineral salts on its journey. Magnesium and calcium compounds are the most common ones. If the water ends up with high mineral content, it is known as ‘hard water’.

Water gets collected in aquifers in the ground and water suppliers extract it and pipe it to our homes. You could say that hard water comes from underground porous rock aquifers while soft water comes from surface reservoirs. Furthermore, the amount of water hardness you have to put up with depends on the geology of the area where your domestic water comes from.

Which Areas of the UK Have Hard Water?

Most of the south and east of England have hard water, while most of Wales, Devon, Cornwall, and Northwest England have soft water.


As you can see on the attached map of the UK and Ireland in this article, the hard water areas don’t follow national, county or postcode boundaries. They are entirely dependent on the underlying chalk and limestone geology of the area.

Do I live in a Hard Water Area?

The map shows only approximately whether an area has hard water or not. Don’t forget, it’s where the water comes from that counts, not where you live. If you really want to know, visit your local water company’s website where you will find an online tool that will tell you whether your domestic water is hard or soft. Just enter your postcode in the search box. You can find out who your local water supplier is by looking up your postcode at the Water.org.uk website.

Map of hard water areas in the UK
Map of hard water areas in the UK

Is Hard Water Bad for You?

You might think that all these dissolved minerals in your domestic water will cause problems with your digestive system. Maybe it’s the cause of kidney stones? Well, as far as medical science is aware, hard water doesn’t cause any problems when ingested. In fact, the dissolved salts actually contribute a small amount of the necessary minerals our bodies need. Hard water does, however, cause problems with skin and hair. But, more about that in the next section.

What Negative Effects Will Hard Water Have?

So far, it seems that the minerals dissolved in hard water cause no internal health problems. So are there any other problems in hard water areas? The answer is yes. The hard water problems mainly have to do with household appliance efficiency, bathing, and beauty products. We've explained the negative effects of hard water below:


  1. You’ll find that hard water causes problems with limescale build-up in household appliances. Solids settle out of solution and coat the inside of water heaters, pipes, and nozzles. You’ll also find limescale clogging up shower heads and covering heating elements within kettles and central heating water tanks. In fact, even a limescale coating as thin as 1.5mm on a water heating element can reduce its efficiency by 12%, causing higher utility bills. That’s something you should think about!

  2. With hard water, you’ll need more detergent in the washing machine if you want your clothes to be clean and soft.

  3. Hard water can impact hair dyes and cause them to fade more quickly than expected.

  4. You will end up using more hand and face soap in hard water areas to produce a satisfactory lather. Soap will also produce scum more easily, which will build up on your skin and block pores.

  5. You’ll find that skin moisturisers are less effective on your skin when you use hard water.

  6. Some of the minerals in hard water, such as calcium and iron, form ‘free radicals’. These attack your skin and damage healthy skin cells. Hard water minerals also prevent the natural oils in your skin from doing what they’re meant to do.

  7. Hard water can also cause hair fall, itchiness, and dandruff in the long run.

What Can I Do to Fix These Hard Water Problems?

Now for the science bit!


Let’s talk about preventing water hardness. You can simply use an ‘ion exchange’ water softener. Now, this isn’t as high-tech as it sounds, but you will need a bit of chemistry knowledge to understand what’s going on.

The water softener consists of small round balls, about 1 to 2mm in diameter, made from a special resin. They’re packed into a tube (known as a column) and primed with sodium ions from water softening salt.


Hard water percolates through the column and exchanges its calcium and magnesium ions for sodium ions. The result is that the hard water ions attach themselves to the ion exchange resin and the sodium ions leave the exchanger with the outgoing water. Simple!


Hard water softening process
Hard water softening process

You might have looked inside your dishwasher and noticed a container used to hold what is known as dishwasher salt. Yes, you've guessed it. It’s salt designed for the ion exchange column within the dishwasher. It prevents limescale from building up and allows you to use less detergent. After each use, a salty brine washes over the ion exchange resin to flush away the calcium ions and replace them with sodium ready for the next wash.


Now, a way to treat hard water for use in washing clothes. Have you ever heard of ‘washing soda’? Its chemical name is sodium carbonate and it has the ability to soften water by removing the calcium ions from solution. Sodium carbonate dissolves in water and allows its ‘carbonate’ parts to link up with the dissolved calcium. The resulting compound, calcium carbonate, isn’t soluble so it settles as a precipitate.

Commercial Water Softeners

Luckily, the manufacturers of ion exchange water softeners make it really easy for us. These water softeners either come already built into the appliance and all you have to do is add salt, or you can buy cartridges containing the resin which plug into a holder within the water stream. After a certain amount of time, you simply have to replace the cartridge with a new one.

Keep Your Water Soft

We hope you found this information useful! As we said earlier in the article, you just need to understand a little bit of chemistry to get the basics of hard water and its effects.


All you have to remember is that areas with chalk or limestone rocks get hard water. There are manufacturers who supply water fittings designed to deal with hard water both as drinking water and washing water. Keep your eyes peeled for such products and check out StoneStream's hard water filtering shower heads and accessories. They will certainly make life much more comfortable for you and your family.


Thanks for reading!


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