What Is TDS (Total Dissolved Solids) And How To Reduce TDS In Water?

Did you know that about three to four million people die from waterborne diseases? More than a billion people do not have any access to safe drinking water. Are you worried about the quality of your drinking water? The best and the easiest way to determine the quality of water is to check the TDS level of your water.

This article will give you a clear-cut understanding of TDS (Total Dissolved Solids), its effects on our body, and how we can reduce the level of TDS in the water we consume.


What Is TDS?


TDS is an acronym for Total Dissolved Solids. Total Dissolved Solids is the total concentration of all the dissolved inorganic salts, organic materials, metals, minerals, and other substances in a particular volume of water.

In simple terms, TDS refers to the organic and inorganic substance found in water that is larger than two microns.

Inorganic salts include calcium, magnesium, potassium, sodium, bicarbonates, chlorides, and sulfate, while pollutants, herbicides, and hydrocarbons are organic materials. You will find these solids in the form of molecules, ions, and micro-granular solvents.

TDS is measured in terms of parts per million (ppm) or milligram per liter. According to the Bureau of Indian Standards, the recommended limit is 500 mg/l. The lower the TDS level, the better and safer your drinking water is.

So, to know if you are drinking safe water, get the water tested and make sure the TDS level is below 500 mg/l.


Reason For A High Level Of TDS In Water

How Much TDS In Water Is Good For Health

There are numerous reasons for the high level of organic and inorganic solids in water. Some of them include-

  1. Natural sources and mineral springs (Water runs over rocks and picks up different minerals found in the rocks.)
  2. Agricultural runoff (Pesticides and fertilizers mixed with water.)
  3. Industrial sewage and waste
  4. Urban runoff
  5. Carbon deposits
  6. Salt deposits and seawater intrusion
  7. Chemicals used for the water treatment process
  8. Plumbing pipes and hardware

Apart from this, TDS level increases due to minerals like nitrogen, sulfur, calcium bicarbonate, etc. found in the air.


Is TDS Bad For You?

As mentioned above, TDS consists of both organic and inorganic substances. Some of this organic matter is good for your body, while others are hazardous. So, the amount and type of solvents present in the water determine whether the water is good or bad.

The US Environmental Protection Agency (US EPA) considers TDS as a secondary drinking water standard. According to them, less than 300 mg/l is a good range for drinking water.

Less than 50 mg/l indicates a lack of natural nutrients and minerals, and hence it is not acceptable. Also, a very low level of TDS will also result in water tasting flat or even bitter.

To sum it up, TDS concentration in water is not necessarily hazardous. It becomes unhealthy when it is too low or too high. The healthiest range is 150- 250 mg/l.


Why Should We Measure The TDS Level In Water?

The primary reason for measuring the TDS level would be to know the quality of the water you consume. A high TDS level may indicate that there are more harmful chemicals present which causes

  • scale build-up in pipes and valves,
  • performance failure,
  • corrosion,
  • high maintenance cost.

A high TDS level might also indicate that the water is hard. Shampoos, soaps, and other cleaning products do not work efficiently in hard water, so rinsing off products will be difficult. However, even if the TDS level is low, it can lead to problems like the corrosion of metals and fixtures.


Other Reasons To Test Your Water’s TDS Level

Some other reasons to test your TDS level include-

  • Taste difference-The water might have a salty or bitter, or sulfuric taste to it. The taste depends on the type of solvents present in the water. It is because of this that low TDS level water tastes almost flat and dull.
  • Cooking-Just like water taste is altered, the food taste also changes if we use the same water while cooking.
  • Health reasons- As mentioned above, if the water contains more harmful substances, it is dangerous to consume.
  • Maintenance of appliances- Scales built up in pipes and valves when there is a high concentration of substances like calcium, magnesium, etc. it also affects the working of your water filtration system, which means that the appliance’s lifespan gets shorter.
  • Colour change and stains- Due to the high level of minerals, there is a chance for the color from clothes to fade. Also, it might leave stains or spots on the utensils due to corrosion.


How To Measure TDS level?

We can measure TDS levels in water using two methods.

1. Gravimetric Method

In this process, we evaporate the water, and the remaining water is measured to calculate the TDS level. This method is accurate if there is a high TDS concentration, especially inorganic salts, but it is time-consuming.


2. Electrical Conductivity

Compared to the gravimetric method, this method is less time-consuming but not as accurate. TDS meters analyze water’s electrical conductivity, which is directly proportional to the concentration of dissolvents in water.


How To Reduce Unhealthy TDS In Water?

First, test the level of TDS in your water supply, and if it is above the recommended level, you might want to consider the following methods. The most effective three ways to reduce the unhealthy TDS level in water are listed below.

1. Reverse Osmosis

Reverse Osmosis

In reverse osmosis, the comminated tap water passes through a semipermeable membrane. The design is such that only pure water molecules pass through. Apart from filtering the harmful toxins like lead, mercury, arsenic, etc.,

RO also filters 90% of the valuable minerals such as calcium, potassium, magnesium, etc. However, this leaves the water tasting dull and flat.

But, most RO filters are equipped with a mineral bed that can add back the lost minerals. It also increases the pH level, thus decreasing the corrosive property.

If the TDS level is more than 500gm/l, this is the most effective treatment solution.


2. Distillation

In simple terms, distillation happens through evaporation. Upon heating the boiling chamber, the water boils and forms water vapors. The evaporated water rises to the cool surface, and then it condenses back into the liquid form in a different container.

Since most impure salts cannot vaporize, it stays in the liquid form in the boiling chamber. The water that condenses back into the second container is safe to consume.

However, there are times when some of these salts vaporize. So, it is not considered as efficient as the RO filtration method. Also, another drawback of this method is that it is a long and time-consuming process.


3. De-Ionization

Water is a mix of positive ions (cations) and negative ions (anions). So, during the de-ionization process, water moves through a membrane with positive and negative electrodes.

Here, the positive ions in TDS detach from the water molecules and attach themselves to the negative electrodes. This results in de-ionization or de-ionized water.

However, for this method to work, the water first needs to pass through reverse osmosis filtration to remove the non-ionic impurities. Again, just like distillation, this process is long and time-consuming.


How To Treat Good TDS In Water?

We saw three methods to reduce the bad TDS in water. Now, we will look at what can be done with healthy TDS. To retain the good TDS in water, you will need a system that only filters the impurities while maintaining the good minerals like calcium and magnesium.

A reverse osmosis system (including a mineral bed) is the best option here.


You May Also Like To Read:

What Is Hard Water? Does It Do Any Harm?

How To Convert Hard Water Into Soft Water



Whether the water is of good quality or not depends on the quantity of good and bad substance TDS present in water. The healthiest range for TDS is 150-250 ml/l.

So, if the TDS level for your drinking water goes either above or below, then you should worry. The main reason is that it will affect your overall health. The best solution to control the TDS level is the RO filtration system.

Has RO filtration been beneficial for you? Would you recommend this to others who face the same problem? Please let us know in the comment section.

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I am tech writer who is passionate about technology and spearheads the core writing team on tech news

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