Difference between Hardness and TDS – (Major Issues Hardness vs TDS)

Water is a compound, made of H2O molecules. Without water, there is no existence of life on the planet. It is a most essential element. We use water in many different ways in our daily life like drinking, washing, other household needs, and on large scale at industries. We use water in critical ways so there is a need of ensuring the quality of water. Measuring the water quality is really important. You can test water quality in many chemical and physical parameters. Physical parameters include its color, odor, etc. And chemical parameters include electrical conductivity, pH, total solids, the hardness of water, and total dissolved solids.

The main difference between TDS and hardness is that TDS hard water consists of organic and inorganic substances that cannot filter out through any filter paper. The hardness of the water exists due to the presence of magnesium and calcium salts of carbonate, chloride, and sulfate. Total Dissolved Solid or TDS pertain to inorganic salts and some amount of organic compounds can dissolve in water. Water hardness refers to water that has a high amount of mineral content.

Total Dissolved Solid (TDS)

DS (Dissolved Salts) in TDS (Total Dissolved Salts) mentions any mineral, metals, salts, anions, and cations that are mixed or dissolved in water. Now here is necessary to define TDS. The T in TDS refers to Dissolved Salts along with the traced amount of organic materials that are dissolved in water. We consider TDS when we want to analyze the quality of water of rivers, streams, lakes as well as drinking water mostly. TDS is a chemical parameter to test the quality of water.

Through TDS, we find out anything that is present in water except H2O. These small particles of dissolved solids cannot filter through a filter paper that has 2-micrometer pores. The soft water TDS level was measured in ppm (parts per million). Generally, explaining the TDS, cations and anions are dissolved in water.

Measuring TDS:

Most people search for how to measure TDS. There are two ways through which you can do this.

1. Gravimetric Method
2. Electrical Conductivity Method

In the gravimetric method, the liquid evaporates. It is a traditional method and time taking process. The residue that is left behind after evaporating the liquid is TDS and it is weighed to measure the quantity of TDS. Although this method takes time but perfects to get accurate results.

In the electrical conductivity method, a TDS meter measures the TDS of water. Here most people have questions in mind that what does a TDS meter measure and how to use a TDS meter? The simple and accurate answer is it measures the presence of everything except H2O in water. The concentration of ions present in water is directly proportional to the electrical conductivity of the water sample. We measure the TDS through the TDS meter for different purposes. It is done for river, lake, and stream testing, swimming pools, agriculture, and hydrophobic cultivations, and other water-related problems.

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Water Hardness

The hardness of water is basically the presence of high mineral content in water. This high mineral content dissolves in water when water flows through limestone and chalk. These rocks consist of magnesium and calcium carbonates and dissolve in water to make them hard. There are two types of water hardness:

1. Temporary Hardness
2. Permanent Hardness

Temporary Hardness:

Magnesium and calcium carbonates are dissolvable in water. When these bicarbonates minerals are dissolved or present in water, they make the water temporary hard. These minerals form carbonate and bicarbonate anions along with calcium and magnesium cations when mixed in water. Water hardness through these bicarbonates minerals is temporary and can be removed by boiling water or adding lime in hard water.

Permanent Hardness:

The permanent hardness of water occurs when sulfates and chlorides of calcium and magnesium dissolve in water. When the water is heated, these minerals are not hasty. That’s why permanent hardness cannot be removed by adding lime or boiling water. To remove permanent hardness, you need to use a water softening system.

Measuring Water Hardness:

Measuring the water hardness is very easy. It is measured in mol/L or mmol/L units. The simple method of testing water hardness testing is through a soap test kit. You required a little bottle or testing kit with a line marked on it. Add water to the line and then add a drop of soap. After this shake the bottle and look for suds. If suds appear, it means water is good and if not that means it is hard water. Adding more drops of soap will lead to more degrees of hardness.

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 TDS vs Hardness

Hardness	TDS
Hardness is defined as the presence of high mineral content dissolved in water.	TDS abbreviates for Total Dissolved Solids.
The hardness of water occurs due to calcium and magnesium carbonates or their chlorides and sulfates.	TDS occurs due to organic matters and inorganic salts when they are dissolved in water.
It is measured either through laboratory test to simply through water hardness testing kits.	It measured by gravimetric method and electrical conductivity analysis.
Unit of measurement is mol/L or mmol/L	Unit of measurement is ppm
Hard water causes a white layer on any surface where it is used e.g. white layer on the shower, walls, etc. And it changes the taste of water.	Measurement of TDS are beneficial for river, stream, lake and swimming pool testing, etc.

How To Test Water Hardness With A TDS Meter

TDS stands for Total Dissolved Solids. It’s the measure of all of the material which is dissolved in your water. A TDS meter actually measures the electrical conductivity of the water, after which it calculates the TDS value. One thing you can’t do with a TDS meter is to use it to figure out how well your softener is working. This doesn’t work because of the nature of how water softening works. A water softener is an ion-exchange device – it grabs on to calcium and magnesium ions (aka hardness) and exchanges them for sodium. Well, sodium carries the same electrical charge as hardness. So the TDS reading of hard water and soft water is pretty much identical even if the water has softened perfectly.

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Frequently Asked Questions (FAQs)

1. Can water softeners reduce TDS?

We use water softeners to reduce the number of hard minerals in your home’s water. However, water softeners do not reduce total dissolved solids (TDS). TDS is the measure of all matter which dissolves in the water – inorganic and organic. When water flows through the softening unit, it will pass through a resin and chemical matrix (called Zeolite) that will exchange the calcium and magnesium ions with sodium ions (salt).

2. Are TDS and hardness the same?

TDS and hardness are water quality parameters. The main difference between TDS and hardness is that TDS include inorganic and organic substances that cannot be filtered through a filter paper. However, hardness is due to the presence of magnesium and calcium salts of carbonate, sulfate, and chloride.

3. Can hardness be higher than TDS?

When there is hard water, the specific quantity of the TDS is made up of hardness minerals, but a lot of it won’t be. So, your TDS value will always be significantly higher than the hardness value. The other thing you can’t do with a TDS meter is to use it to figure out how well your softener is working. This doesn’t work because of the nature of how water softening works.

4. Is low TDS water is harmful?

Low TDS water is defined as that containing between one and 100 milligrams per liter (mg/L) of total dissolved solids (TDS). This is typical of the water quality obtained from distillation, reverse osmosis, and deionization point-of-use water treatment available to consumers in the world. However, scientific data clearly demonstrate that the consumption of low TDS water will not lead to harmful effects on the human body.

5. What affects water hardness?

Hardness is caused by compounds of calcium and magnesium, and by a variety of other metals. General guidelines for classification of waters are 0 to 60 mg/L (milligrams per liter) as calcium carbonate is classified as soft; 61 to 120 mg/L as moderately hard; 121 to 180 mg/L as hard; and more than 180 mg/L as very hard.

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Conclusion

Concluding that whether it is TDS or hard water, both are harmful to your health. TDS consists of inorganic salts and dissolved organic elements that cannot filter through a filter paper. Whereas hardness is due to the dissolving of calcium and magnesium carbonates. Both of them make the water totally another type of water that is harmful. Always keep it analyzing whether your water taste or color is changing or not to make sure use of pure water for better health.