What is TDS in Drinking Water?

tds in drinking water

Water is one of the greatest needs of humans. Good water promotes good health. But nowadays, in the era of industrialization, water in most cities is no longer fit for drinking. This is the reason why the trend of water purifiers is increasing very fast. This water purifier maintains the TDS level in water. But do you know what TDS is, how water purifiers work, and how many types are there?

Rahim says, value water, for there is nothing without it. The importance of this couplet of Rahim Das ji increases even more when the water is pure and full of minerals. We all know that there is 60 to 70% water in our body, that is, there is water in every part of our body, even in the bones. Cannot survive without water for more than 7 days.

With the help of water, toxic substances are released from the body; In the form of sweat or urine. For this reason water helps in keeping us healthy.

But while drinking water, it is important to keep in mind what kind of water you are drinking, whether the water is clean and pure. RO or UV water is considered pure and safe to drink, but does it cause any harm? Let us know through this article what kind of water is suitable for drinking, what should be the amount of TDS in it, what are its benefits and how much harm does it cause?

Importance of TDS in Drinking Water

Water is a good solvent and dirt dissolves easily in it. Pure water – tasteless, colourless, and odorless is called universal solvent. Dissolved solids refers to any mineral, salt, metal, grain or ions dissolved in water. Total dissolved solids (TDS) include inorganic salts (mainly calcium, magnesium, potassium, sodium, bicarbonate, chlorides and sulphates) and some small amounts of organic matter dissolved in water and especially in groundwater. Nitrates are also found in water.

TDS is expressed in units of mg per unit volume (mg/liter) or also referred to as parts per million (ppm). TDS is generally not considered a primary pollutant (ie it is not thought to be associated with health effects). It is used to see whether water is pure or potable or not and TDS also indicates whether it contains chemical contaminants or not.

Water can be classified by the level of TDS:

  • Freshwater: Less than 500 mg/litre i.e. TDS = 0.5 ppt
  • Brackish water: 500 to 30,000 mg/litre i.e. TDS = 0.5-30 ppt.
  • Saline water: 30,000 to 40,000 mg/litre i.e. TDS = 30-40 ppt.
  • Hypersaline water: more than 40,000 mg/litre i.e. TDS >= 40 ppt

Therefore, the total dissolved solids test is used as an indicator test to determine the general quality of water. Sources of dissolved solids include all dissolved solids and ions, but the following table can be used as a generalization of the relationship of TDS to water quality problems.

  • Cations combined with carbonates i.e. CaCO3, MgCO3 etc. – are associated with hardness or bitter taste.
  • Cations associated with chlorides i.e. NaCl, KCl etc. – Salty or saline taste, are associated with increased corrosiveness.

Therefore, it is said that the taste of water is associated with different TDS concentrations. If you are not sure about the hardness of water, you can test it with the help of a TDS meter device. TDS value of 500 mg/litre of water is considered very harsh. The most commonly used purification systems to reduce TDS are carbon filters and reverse osmosis (RO).

Let us know about different types of purification systems


RO means Reverse Osmosis. In Industrial RO Plant, commercial RO Plant or home RO water purifier, water is passed through a pump to increase the pressure of the water and then passes this pressurized water through the RO membrane (semi permeable). In this process, dissolved solids and TDS present in water are eliminated. Reverse Osmosis converts hard water into soft water. But the disadvantage of using RO water purifier is that it produces a lot of waste water.

Matter: Definition and their states


UV water purifier uses UV radiation to kill reagents, microorganisms. The UV radiation source purifies the water through the tube. UV water purifier is recommended to be used for soft water, which contains contaminants.


UF means ultra filtration. UF water purifier consists of a threaded membrane made of hollow fiber. UF removes unnecessary materials, suspended solids and other large molecular weight materials from water which are harmful to human health. UF water purifier works even without electricity.

Is water with low TDS harmful?

In fact, lower TDS in drinking water is generally better but everything has a limit, it is also mandatory to have minerals in the water so our aim is not to reduce TDS to zero. Our body also needs some minerals. The amount of salt in the blood is a little less than 1% and anytime you drink water with less than 1% of it, you are losing electrolytes.

From the above article it is known that TDS does not purify water but it tells whether water is potable or not and how other water purifiers purify water and make it potable.