Hard Water vs. Soft Water – What’s the Difference?

I am certain we have all heard of “hard water” and “soft water” used to describe the water supplies in our homes. The water we drink actually contains more than just water;

it comprises of beneficial minerals and nutrients too. The amount of these minerals in the water we drink determines whether it is “soft” or “hard”.

You might be wondering why the hardness of our water is at all relevant, but actually, there are several differences between the two types of water. Is there one more beneficial to our health? How do I change the hardness of my water? Keep reading to find out.

What is water hardness?

Even purified drinking water that we get from our taps contains more than just water. There are minerals found in our drinking water, with the two most important being magnesium and calcium. Hard water contains more of these minerals, whereas soft water contains more sodium.

When it precipitates, rainwater that falls is naturally soft, but as the water hits the ground and runs through different rock formations it picks up different minerals. Water is a good solvent and so easily dissolves and holds onto calcium and magnesium and becomes hard.

The hardness of water, therefore, varies across the states depending on the rocks that the groundwater has passed through. An area with more limestone will release more calcium into the water supplies, for example. For land with large granite deposits, fewer minerals are released, and water will be softer.

According to the World Health Organization (WHO), water containing calcium carbonate concentrations of below 60mg/L is classified as soft, between 60 – 120mg/L is moderately hard, 120 – 180mg/L is hard, and anything greater than 180mg/L is very hard water.

How do I know if my water is hard or soft?

hard water vs soft water

Hard and soft water look identical, so how can we tell the difference? There are several signs of having hard water in your home:

  • Spotty Glasses: If when washing your glassware there are white spots or streaks, your water is likely hard. These marks are calcium carbonate deposits left behind after washing.
  • Mineral Stains: Similarly, mineral staining on clothes that have just been washed are another sign. Clothes can wear out faster when washed with hard water.
  • Fewer Bubbles: Soap does not lather as well in hard water, so there will be fewer suds when washing with hard water.
  • Soap Scum: Soap reacts with the high levels of calcium in hard water and forms soap scum which is left around your sinks, baths, and showers. Hands can also feel as if they have a film over them after washing.
  • Lower Water Pressure: The mineral deposits can build up in your pipes, restricting the water flow and reducing water pressure.
  • Limescale Build-up: Mineral deposits can also form in your kettle and dishwasher, or any appliance where water is heated. This can reduce the life expectancy of appliances.

If you experience none of these signs, then the water in your home is likely soft. Signs of soft water include a healthy lather, cleaner clothes, and good water pressure. Soft water may also have a slightly salty taste due to the high sodium content.

Which water is best for my health?

hard vs soft water

Both hard and soft water are perfectly safe to drink, but it is thought that hard water is more beneficial as it contains higher quantities of essential minerals that our bodies need.

Therefore, drinking hard water may help you reach your recommended daily intake of magnesium and calcium.

There is also speculation that drinking harder water could potentially decrease the risk of developing cardiovascular disease. The study found that drinking water with calcium carbonate concentrations of 40 – 80mg/L could be beneficial.

According to WHO’s classification, this is the level of calcium found predominantly in moderately hard water. There is yet to be truly conclusive evidence to support this claim through.

When using water for washing our bodies, soft water is more beneficial. Hard water can lead to dry skin, hair, and a flaky scalp. People with eczema could be especially vulnerable when washing in harder water as the minerals can alter the pH balance of the skin which weakens its’ barrier to bacteria and infections.

There are also concerns for people with high blood pressure drinking soft water because of the higher sodium content. Similar to consuming excess salt through your diet, consuming high levels of sodium through your water source can exacerbate high blood pressure.

Having said that, neither water is bad for your health. If living in an area with soft water, ensuring you eat a well-balanced diet or taking magnesium and calcium supplements can counteract the lower mineral concentrations.

If living in an area with hard water and have dry skin, try talking to a dermatologist about products to combat this. You could also look into softening your water at home, although this is not recommended for those with high blood pressure.

Which water is best for my home?

difference between hard and soft water

Although both water types have health benefits and drawbacks, when it comes to problems in the home hard water is always the culprit.  The main reason for this is the reaction of the minerals with soap and detergents by leaving behind soap scum, making cleaning more difficult, and clogging up pipes.

Due to the high levels of minerals dissolved already in the hard water, soaps and shampoo cannot dissolve in the water as easily. In other words, the calcium and magnesium are taking up the “space” in the water that the soaps would usually bind to.

This both leaves behind a nasty scum in your sinks and also ramps up the cost of your cleaning products as more soaps are needed to create a proper lather.

When hard water is heated, the calcium in the water also reacts and forms limescale, an unsightly white build-up on the inside of your kettle, pipes, and dishwashers.

This can block pipes and taps causing reduced water pressure and shortening the life span of your home appliances. This results in more repairs meaning, once again, more expenditure.

Limescale is also a breeding ground for bacteria so it can cause impurities to be introduced back into your water. You might also find scum or limescale floating around in your hot drinks, which is unappealing and unappetizing.

How can I soften my water at home?

soft vs hard water

After reading all the hard water problems, you might be wondering how you can soften your water at home. There is a relatively simple way to do this. Hard water is passed through a resin that is coated in positive ions, usually sodium ions.

Water favors sodium over calcium and magnesium, so when it runs through the filter it drops off these minerals and picks up the sodium instead. It does a little ion exchange.  For more information on how water softeners work, take a look at this video.

YouTube video


The water softening systems do need frequent maintenance and sodium needs to be added regularly to ensure there are enough sodium ions in the system to carry out the ion exchange.

Water softeners can also become breeding grounds for microorganisms like bacteria if not cleaned properly, so the equipment must be well maintained.

There are several different water softeners on the market, but this video runs through some of the best available. Which water softener you choose for your home should be based on your individual needs determined by the quality of water in your area.

It is therefore important to contact the local water provider to gain an assessment. Water softening manufactures will be happy to help you find a suitable system. The only major concern for using a home water softener is for people with high blood pressure or those that are on a low-sodium diet.

If too much sodium is added to the water then this can have negative impacts, so always speak to the manufacturer to find out exactly what the sodium levels could reach. Alternatively, use a water softener that uses another ion in place of sodium such as potassium.

Final Word

soft water

Hopefully, this article has answered all your questions on hard and soft water. The most important take-home points for this are:

  • Hard water contains more of the minerals calcium and magnesium, whereas soft water contains more sodium
  • Both soft and hard water can safely be drunk by the majority of people
  • Hard water can cause problems in the home relating to cleaning and can ramp up bills as a by-product
  • Hard water can be softened in the home using a water softener by exchanging calcium and magnesium with sodium
  • People with high blood pressure should take precautions when using a water softener

Have you noticed signs of hard water in your home? Are you thinking of or do you already use a water softener? Let us know below in the comments.

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