Hard Water vs Soft Water: What are the Differences, Benefits & Risks?

Have you ever heard this, that hard water is good for our bones, yet soft water is better for our skin? There is a raft of rather confusing information for us to make sense of.  What is not a secret is that water is an essential element of human life.As the body excretes various amounts of water through sweat, urination and even breathing, your body needs to constantly replenish those fluids. In fact, we would only survive without fresh water for a matter of days. 

Given we need to consume a consistent amount throughout the day for optimal hydration, it is important we review the type and quality of the water we are drinking.

This might be hard to believe, but water is water, right?  But there is actually a scale upon which water is deemed ‘hard’ or ‘soft’, given the concentration of certain minerals and chemicals in its composition,as the presence of these minerals will ‘harden’ the water, and their absence will leave it ‘softer’. 

In this article, we will compare hard water vs soft water in terms of their differences, benefits, and risks.


What is hard water?

 Hard water is water that contains a high level of natural minerals, such as calcium and magnesium. This typically occurs as free-flowing water passes through soils or by rocks with elements like chalk, limestone and dolomite and retains certain properties in its makeup. 


Advantages of hard water

 Hard water holds essential minerals that can deliver a range of health benefits. There is a selection of studies that believe a correlation may exist between the prevention of cardiovascular disease and other health conditions from drinking hard water, and whilst further research is required,magnesium and calcium levels are believed to be what deliver these health benefits. Soft water lacking these minerals, therefore, can potentially lead to various health conditions.


Disadvantages of hard water

You won’t find serious health effects from drinking and using hard water,in addition, hard water, can provide an important supplementary contribution to total calcium and magnesium intake. However, many people do recognise it can contribute to drying their skin and hair. The high amount of minerals present can also counteract the activities of detergents, leaving a range of greyish residue on both dishware and clothing.


Hard water can also form a precipitate (solid) when the water is heated, which can coat the inside of pipes and appliances thus reducing the flow of water. In addition, the precipitate (dissolved minerals which fall out of solution and form a solid) can damage plumbing fixtures and appliances over time, especially when applied in industrial settings.  The most common sources of hardness come from limestone, which introduces calcium into the water and dolomite which introduces magnesium into the water.

The effects of hard water on the body

Drinking hard water can help you achieve your recommended daily intake of key minerals, and as mentioned above, serious illness is not linked to consuming hard water.  

Some studies have shown promising outcomes when it comes to cardiovascular health, but there are many variables and outcomes that are not yet fully evaluated. Other studies have shown a protective effect against gastric cancers of calcium intake from drinking hard water.Magnesium also showed promise in fighting gastric cancer, and lowering the risk of esophageal and ovarian cancer.

Further studies have also indicated magnesium found in hard water decreases the risk of cerebrovascular disease and proves beneficial to those with borderline magnesium deficiency. It was even advised to cook using hard water to reduce the amount of magnesium lost from food in the process, as well as its high bioavailability.

Magnesium sulphate is also said to decrease the risk of eclampsia by up to 50%, as well as the risk of maternal mortality.

Even gut health can potentially benefit from hard water, alleviating the onset of constipation by 85%, thanks to a combination of calcium and magnesium.


What is soft water?

Soft water contains a low level of minerals. Rainwater is an excellent example of this, as it only becomes hard after collecting minerals whilst running across the earth’s surface. Other sources often come from acts of water filtration through a water purifier to create what is known as ‘pure water’.


Advantages of soft water

 Soft water works well to dissolve detergents and soaps for general cleaning purposes, not leaving any mineral stains or soap scum. This extends to cleaning ourselves, as it leaves our skin feeling healthy. As soft water does not form a precipitate when heated, it is lesslikely to damage plumbing fixtures and appliances


Disadvantages of soft water

Without the same collection of minerals, soft water isn’t as beneficial to drink, and it will lose some taste provided by these minerals. Soft water can also more easily collect unwanted elements and contaminants, especially as it passes through pipes, such as lead. Higher levels of sodium present may also be detrimental to those with a sensitivity to large amounts of saline, particular those with high blood pressure or kidney issues.

What’s the difference between hard water and soft water?

 So, what are the differences between hard water and soft water? Simply put, hard water contains a high level of minerals collected from the earth, namely calcium and magnesium, while soft water contains a low level of these minerals. As such, each has its own uses and functions, with hard water holding more benefits for the health of the body, but not in household cleaning applications, whereas soft water works in the reverse.


Various water purifiers and water filtration methods are available to conduct a process known as ‘water softening’, which places hard water through a system to remove various minerals and create pure water. 


The level of water hardness

Level of Water Hardness

Calcium & Magnesium (parts per million)


Under 17

Slightly Hard

17 to 60

Moderately Hard

60 to 120


120 to 180

Very Hard

Over 180

Truths & Myths About Soft and Hard Water

Myth: Hard water is contaminated

While hard water is technically filled with minerals and chemicals it has collected along its various journeys, this does not constitute ‘contamination’. In fact, these minerals are good for our health and drinking hard water can provide a range of health benefits.

Myth: Hard water tastes bad

Minerals are what give water its taste. Given the higher amount of sodium, it may also taste extra salty. 

Myth: As it is natural, rainwater must be hard water 

Rainwater is actually soft water when it falls to the ground, but as it passes through various types of soils and rocks, it collects a variety of minerals, including calcium and magnesium, that then increase its hardness.

zazen Alkaline Water has a “moderately hard” hardness value.  This is from a combination of minerals including calcium and magnesium.  

If you are keen to improve your health outcomes, a great place to start is hydrating with our balanced mineralised water that is the zazen Alkaline Water System.


Fisher J, Roland J, Hard Water vs. Soft Water: Which One is Healthier?, Healthline, July 2019 https://www.healthline.com/health/hard-water-and-soft-water 

Sengupta P. Potential health impacts of hard water. Int J Prev Med. 2013 Aug;4(8):866-75. PMID: 24049611; PMCID: PMC3775162.

Sunrise Specialty, Hard Water vs. Soft Water: What’s The Difference? 2022 https://www.sunrisespecialty.com/hard-water-vs-soft-water 

Nerbrand C, Agréus L, Lenner RA, Nyberg P, Svärdsudd K. The influence of calcium and magnesium in drinking water and diet on cardiovascular risk factors in individuals living in hard and soft water areas with differences in cardiovascular mortality. BMC Public Health. 2003 Jun 18;3:21. doi: 10.1186/1471-2458-3-21. PMID: 12814520; PMCID: PMC198279.

Friendly Water, The Simple Way Soft Water Users Help the Environment, September 2021, https://friendlywater.co.uk/blog/the-simple-way-soft-water-users-help-the-environment#:~:text=Soft%20water%20will%20boil%20faster,t%20lather%20easily%20with%20soap

Brennan D, Difference Between Hard Water and Soft Water, Nourish by WebMD, June 2021 https://www.webmd.com/diet/difference-between-hard-soft-water 

Janiszewski P. (2011). The science of starvation: How long can humans survive without food or water.

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