Hard Water vs Soft Water, Where Comes the Difference?

Have you ever wondered why water tastes different in different places? Or why sometimes the water feels slippery when you shower as if something is left on your skin?  Along with the strengths and weaknesses, this article will give you some tips about hard water and soft water.

What is Hard Water vs Soft Water?

These two types of water are based on the amount of dissolved minerals to classify, primarily calcium and magnesium ions in the water.

Water Type Calcium and Magnesium Levels (ppm)
Soft Water < 60 ppm
Moderately Hard Water 60-120 ppm
Hard Water 120-180 ppm
Very Hard Water > 180 ppm

Hard water typically contains high concentrations of these minerals, which are often caused as water flows through geological formations like limestone and gypsum. In daily life, examples of water sources that often contain hard water include groundwater from wells, rivers flowing through mineral-rich areas, spring water and lakes fed by natural mineral deposits.

On the contrary, soft water typically has lower mineral content, meaning decreased levels of alkaline substances like calcium carbonate and magnesium carbonate, thus getting a lower pH compared to hard water. Soft water can form naturally, such as the common rainwater. Also, soft water can be obtained through a treatment process that involves removing or replacing calcium and magnesium ions.

hard water vs soft water

How Hard Water vs. Soft Water Beneficial?

Hard water

For individuals with high blood pressure, the abundant minerals in hard water can help prevent blood vessel spasms thus maintain normal blood pressure levels. Additionally, the minerals found in hard water can benefit bone health and support proper nervous system function.

Soft water

Soft water, with its low mineral content, can be utilized in various fields for its distinct benefits:

  • For Household Use:

Soft water, because it does not form calcium carbonate and magnesium carbonate deposits, prevents pipe blockages. This can extend the lifespan of various home appliances and save on energy costs. Unlike hard water, soft water is more suitable for household drinking water. It tastes better and can help reduce the risk of kidney stones, indigestion, and arteriosclerosis.

  • For Industrial Use:

In certain industrial production processes, strict mineral content requirements in the input water are essential to ensure stable equipment operation and product quality. In such cases, soft water is a necessity. For example, in the electronics and semiconductor industries, soft water prevents damage and contamination of delicate components and reduces heat loss. In the pharmaceutical industry, distilled soft water is required for injection water to avoid adverse reactions. Additionally, using soft water for boiler feedwater ensures efficient heat transfer in equipment.

  • For Commercial Use:

Soft water offers significant advantages in the cleaning industry, providing spot-free and spot-free cleaning results while reducing the need for detergents and cutting costs. It is widely used in car wash services, high-rise building window cleaning, dry cleaning services, and cleaning requirements in restaurants and hotels.

In the skincare and cosmetics industry, soft water enhances product effectiveness and ensures skin health. Using softened water in aquariums not only maintains the health of animals like moon jellyfish but also ensures clean and transparent glass, enhancing the visitor’s viewing experience.

soft water appliance

Disadvantages of Hard Water & Soft Water?

Hard water:Hard water significantly impacts household appliances and pipe maintenance. The minerals in hard water tend to deposit on the inner walls of pipes, increasing resistance and causing blockages, which raises maintenance costs. Additionally, prolonged use of hard water can lead to dry hair and rough skin. Hard water also reduces the cleaning effectiveness of soap, leaving residues on clothes and affecting their quality.

In industrial and commercial sectors, hard water can severely compromise product performance. For instance, in the textile industry, hard water can make products stiff and prone to breakage. In hotels, hard water may leave spots on glassware, harming the establishment’s reputation.

disadvantages of hard water

Soft water:Soft water does have a drawback. It is not suitable for watering plants. Typically, the softening process for hard water uses ion exchange technology, where sodium ions replace the calcium and magnesium ions in the water, thus softening it. As a result, softened water contains a higher concentration of sodium ions. Prolonged use of soft water for irrigation can lead to salt accumulation in the garden, which can be detrimental to plant growth.

How Can I Tell Hard Water vs. Soft Water?

Here are a few simple and convenient methods to test whether the water in your area is hard or soft:

1)Soap Test: Add soap to hot water and stir gently. If a lot of scum forms, the water is hard; if not, the water is soft.

2)Heating Method: Boil the water. If a lot of scale deposits are left on the heating equipment, the water is hard; otherwise, it is soft.

3)Hardness Test Strips: Dip a test strip into the water and observe the color change to determine the water’s hardness.

For industrial applications, where meeting specific water quality standards is crucial, more accurate testing methods are recommended. You can send water samples to a professional laboratory for precise calcium and magnesium ion content analysis.

How to Change Hard Water to Soft Water?

If you are looking for methods to make hard water soft, here are some commonly used softening techniques:

Reverse Osmosis (RO):

The pressure difference exists on the two sides of the RO membrane, ushering in the water numerator while preventing minerals in the reverse osmosis water filter, making hard water softened effectively. The micropores of RO membranes are typically around 0.0001 micrometers, efficiently removing mineral ions, organic compounds, viruses, and bacteria, significantly improving water quality.

Ion Exchange:

Ion exchange utilizes filling exchange tanks with cation and anion exchange resins, which are capable of removing ions from water. Sodium ion exchange resins are commonly used, where calcium and magnesium ions in the water are exchanged with sodium ions on the resin surface, allowing sodium ions to enter the water while calcium and magnesium ions are adsorbed onto the resin, effectively softening hard water. When the sodium ions on the resin surface are depleted, regeneration typically involves rinsing the resin with a cheap sodium salt solution, resulting in low-cost operations.

how ion exchange filter works


Via boiling water, distillation transforms water into steam, which is then condensed back into liquid. Minerals in water, having higher boiling points, do not evaporate with the steam, resulting in reduced calcium and magnesium ion content in the distilled water and thus lowering its hardness. Distillation is typically used for pharmaceutical and laboratory water, not suitable for large-scale industrial applications as an energy-intensive method.


Electrodeionization(EDI) utilizes an electric field to migrate calcium and magnesium ions, which carry positive charges, towards the anode. Selective permeability of the semipermeable membrane allows these ions to pass through while concentrating in the brine chamber and being discharged. Meanwhile, the dilute water chamber obtains softened water. This method produces high-quality water and finds wide application in industrial and scientific research fields.

Note: Regular cleaning of equipment and occasional component replacement are essential for maintaining the continuous and stable operation of any softening treatment method.

How to Choose the Best Water Softener?

How to choose the best softerner

When selecting the best water softener or softening method, understanding the hardness of the water you use is crucial. You can assess this through the methods mentioned earlier for water quality testing and evaluation.

For residential applications, it’s also important to consider pipe sizes and daily water usage to ensure the water softener model matches the household’s needs. In industrial settings, factors such as required water quality, volume to be treated, and composition of the raw water all influence the selection of a suitable softening system, necessitating detailed and professional data reports.

You can further explore the steps to choose the best ion exchange water softener by reading this article.  If you’re finding it difficult to choose a water softener, why not leave your water treatment needs to our technical team? They will provide you with the best and most economical recommendations.


1)Is Bottled Water Hard or Soft?

Bottled water can be either hard or soft, it depends on brands. Generally, you can distinguish them by reading the label on the bottle. If the label says “mineral water,” it is hard water. Mineral water is collected from underground sources or springs, rich in mineral elements, hence it has high hardness.

If the label says “purified water,” it means the water has undergone various processes to remove minerals and impurities, making it soft water.

2)Is Distilled Water Hard or Soft?

Yes, as mentioned earlier, distilled water undergoes evaporation and condensation, removing most minerals and impurities, including calcium and magnesium ions. Therefore, distilled water has low hardness and is considered soft water.

3)Is Soft Water Safe to Drink?

If you’re concerned about low mineral content in soft water and therefore think it’s unsafe, that’s unnecessary. This is because humans primarily obtain necessary minerals from food, and the minerals in water have minimal impact.

However, it’s not advisable to simply replace a water softener with a water purifier. Generally, softened water used for drinking simply reduces the calcium and magnesium ion content in water, and it doesn’t effectively remove most impurities like bacteria, particles, and organic matter as reverse osmosis filters do. Therefore, soft water does not ensure the safety of drinking water.

4)Is There any Water Softener Health Risk?

During the use of water softeners, the membranes and resins inside can accumulate minerals and impurities. Without regular cleaning, this can lead to the growth of harmful bacteria, posing health risks.

Additionally, some water softeners enrich water with sodium ions, which may be problematic for individuals with hypertension who need to restrict sodium intake. It’s advisable for you to consult suppliers about sodium levels in softened water before purchase to avoid exacerbating health conditions.

Update cookies preferences
Scroll to Top