What is TDS and how much of TDS is suitable for drinking water?

TDS level water hozone

You would have often heard this name when you starts looking for your first water purifier. There is a lot of hype about TDS and its value but it is very much confusing to get an clear understanding regarding this. We made it simpler for you through this post.

1. What is TDS?

As per WHO, Total dissolved solids (TDS) is the term used to describe the inorganic salts and small amounts of organic matter present in solution in water.

Example of some of the inorganic salts which are found in water are calcium, magnesium, potassium and sodium, which are all cations, and carbonates, nitrates, bicarbonates, chlorides and sulfates, which are all anions. 

Cations are -ve charged particle and Anions are +ve charged particle that are constituents of compound. Let’s stop this chemistry here.

Therefore,

TDS is the sum of all dissolved solids like carbonates, bicarbonates, chlorides, sulfates, phosphates, nitrates, calcium, magnesium, sodium, potassium, iron, manganese etc. dissolved in water measured in parts per million (ppm) or mg/L.

So,

2. How come these particles get dissolved in water?

The water which we get for our usage are mainly groundwater or surface water. Presence of minerals in water may be from natural or artificial source.  Minerals are inherent part of earth, that’s what which give colors to its surface. So, with rain and river these minerals get mixed with water.

Also because of human activity of using chemicals in farming or industries, these eventually get mixed with surface water sources like canal, river, pond etc or with groundwater.

Concentrations of TDS from natural sources have been found to vary from less than 30 mg/litre to as much as 6000 mg/litre, depending on the solubility of minerals in different geological regions.

TDS meter chart of water hozone
TDS range meter

3. Are these TDS particles or minerals found in water are good?

Some are while some are not.

Following are the minerals which are found in water and are essential for human body growth.

  • Calcium –Vital to the healthy development of bones and teeth.
  • Magnesium – Helps transform food into energy.
  • Potassium – Helps the heart function normally and balances fluid.
  • Sodium –Helps to maintain fluid balance.
  • Copper– Essential to growth and development. Copper also supports the growth of blood cells.
  • Zinc – Helps wounds to heal and supports cell development.
  • Phosphorus – Supports the development of bones and teeth

Where as minerals like arsenic, lead etc are not at all permissible to have in water. These are dangerous for human health.

4. How does TDS value affect our life?

Apart from positive or negative impact on health a water with TDS value higher means having high presence of minerals may affect water pipes and electronic devices negatively.

Certain components of TDS, such as chlorides, sulfates, magnesium, calcium, and carbonates may affect corrosion or encrustation in water-distribution systems.

High TDS levels (>500 mg/liter) result in excessive scaling in water pipes, water heaters, boilers, and household appliances such as kettles and steam irons.

Such scaling and erosion shorten the service life of these appliances.

Water with extremely low concentrations of TDS would be having insipid taste.

5. How to check for TDS value of water in your city?

You can contact water testing labs in your city and they will do testing and let you the results. In such testing three parameters are checked mainly

  • Physical parameter
  • Chemical parameter
  • Microbiological parameter

TDS values comes under physical parameter and is measured in mg/L and often called as ppm.

You can use digital TDS meter to check the TDS level of water at your home. These are available online and you can choose among these

6. Does lower TDS value mean higher purity of water?

For a water free from microbes, as long as value of TDS is less than BIS standard which is 500 mg/L for safe drinking, it is pure drinking water.

It is often seen that sales person will tell you than the TDS value of the water of their RO purifier is less than your UV or UF purifier water, so you need to purchase this as RO to get water of higher purity. That’s not true entirely.

Let’s us see TDS value of some of the drinking water available around us as per taste done by us through digital TDS meter.

Kinley’s average TDS: 17 mg/L

Aquafina’s average TDS: 9 mg/L

BMC(Mumbai) average TDS: 60 mg/L

Tap Water average TDS: 370 mg/L

Himalayan mineral water average TDS: 250 mg/L


Himalayan mineral water is a very reputed brand and a product of TATA group. A higher TDS value of Himalayan mineral water doesn’t make it any less pure for drinking than other packaged drinking water.

Therefore it is clear that a higher value TDS water, as long as it is <500 mg/L is not at all having any negative impact on health. In this regard even National Green Tribuna (NGT) has directed the central government to prohibit them where total dissolved solids (TDS) in water are below 500 mg per litre and sensitise public about the ill effects of demineralised water.

7. What is TDS controller?

You might have come across some RO purifiers that is having mentioned “TDS controller” as extra feature.

TDS controller hozone

TDS Controller is a device that controls the TDS of water. TDS Controller does not filter or purify the water like the filters, cartridges, and membrane.

This is a small device and cost even less than Rs. 100 and often these are sold with RO purifier stating that it will control the flow of minerals in water.

It is having one water output and two water input. There is one screw that is used to control the flow of input water.

RO purifier filters out almost 99% of any foreign element present in water that include essential minerals also.

Now, what to be done if you need to increase mineral presence in the RO water?

There is no any mechanism to selectively filter out some minerals and prevent other across the same RO membrane.

So,

To increase the TDS value in water, TDS controller reduces the water flow through RO membrane because of which less proportion of water get demineralized.

Similarly,
To decrease the TDS value in water, TDS controller increases the water flow through RO membrane because of which more proportion of water get demineralized.

It is not the effective way of doing and not a recommended one as It causes mixing of RO purified water and Non RO purified water which is not at all healthy.

For this purpose alternate solution is to use Mineralizer or Mineral Cartridge.

8. What are the best water purifier for High TDS water supply in my home?

If you are looking for water purifier to mitigate TDS presence in your water supply you can go for these highly recommended water purifier.

KENT Grand+ 8-Litres Wall-Mountable RO + UV/UF

Havells Max RO+ UV+ Mineralizer

Livpure Glo 7-Litre RO + UV + Mineralizer

Blue Star Aristo RO+UV

Most of these RO purifier can purifier water with TDS value upto 2000 mg/L, suitable for bore well, tap, ground water sources.

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