Check water TDS level

So you might be Considering for buying a water purifier and you have come a lot around the term TDS (Total Dissolved Solids) and maybe you already know what TDS is but you want to know how to measure TDS of water at home, so you can buy the water purifier accordingly.

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Here you will know the easy step by step guide to check TDS level of water.

But Let’s 1st understand what is TDS?

TDS (Total Dissolved solids) is the total dissolved and combined organic and inorganic substances present in the water, purest chemical form of water is H2O but in nature water is not find in the complete H2O form it may contain other ions, molecules and other impurities such as dust, clay, heavy metals (harmful for health) such as arsenic, lead, mercury etc and essential minerals also such as Calcium (Ca2+), Magnesium (Mg2+), Sodium (Na+), Potassium (K+) etc. And TDS is calculated by measuring the milligrams of these dissolved substances present in 1 litre of water and to measure this we use a device called TDS meter which shows reading as same in mg/L.

Method 1: How to measure TDS Level of water with TDS Meter?


To Check the TDS level of water:

  1. Step 1: Buy a TDS Meter from Amazon, costs around Rs 250 or if you have one then it’s ok.
  2. Step 2: Take a half glass of your tap water (Source water) or Filtered Water if you want to test what is the TDS after filtration.
  3. Step 3: Press the ON button and dip the TDS meter 1-2 inch deep into the water.
  4. Step 4: Keep the meter like that in water for 10-15 seconds and then press the hold button on TDS meter before taking the meter out of the water.
  5. Step 5: You will find the reading on TDS display, for example 250, 350, 110 depending on water TDS, these reading are in ppm (mg/L) both are same thing. Some meters might show 10X symbol in that case you just have to multiply the reading with 10.
  6. Step 6: Shake the TDS meter to remove any water inside it and put on the protective meter cap.

Method 2: How to measure Water TDS using Filter Paper and a Scale?

filter paper and weighing scale

Measuring TDS with TDS meter is simple, but if you do not have a TDS meter you can measure it using Filter paper and a scale but it will still require you to buy filter paper and the hassle of testing, so measuring with TDS meter is recommended.

Things you will need:

  • One Sterilized glass beaker
  • Water sample (your source water) for measuring TDS levels
  • Filter paper (Find on Amazon)
  • Evaporating Ceramic dish
  • A sterilized stirring stick
  • Pipette large enough to collect a minimum of 50 ml
  • A weighing scale

Measure Water TDS with filter paper and weighing scale:

  1. Step 1 – Take the empty evaporating ceramic dish and clean and sterilized it so that it does not have any dust particles and weigh this empty evaporating dish in milligrams on weighing scale and write the reading on a notebook marked as “A“.
  2. Step 2 – Take the sample water into the sterilized glass beaker and stir the water with stirring stick strongly so that particles present in water may get evenly distributed.
  3. Step 3 – Continue stirring the water and collect 50ml of water with the help of the pipette while stirring the water.
  4. Step 4 – Place another beaker or any utensil below the filter paper and Drop the water from the pipette onto filter paper and repeat the procedure of taking 50ml of water from pipette and pouring it on filter paper 3 more times. So that you get some particulates on filter paper.
  5. Step 5 – Then transfer the particles present on the filter paper to the evaporating dish.
  6. Step 6 – Leave the filtrate (particles) in the evaporating dish to completely dry.
  7. Step 7 – After the filtrate in the evaporating dish is dry, weigh the evaporating dish on weighing scale (with the filtrate) again in mg/L and note it as reading “B”.
  8. Step 8 – Measure the TDS level by subtracting B from A.

    To check TDS level, Use this formula

    TDS = [(B-A) X 1000]/ml sample
    (B = weight of the evaporating dish with the particles in it.
    A= the weight of the evaporating dish alone.
    ml = 50 as we have taken 50ml of water
    Resulted TDS value will be in mg/L)

Frequently asked questions (FAQs)

How much TDS is good for drinking water?

According to Bureau of Indian Standards (BIS) 500mg/L TDS present in water is acceptable for drinking and 300mg/L is called to be Ideal, but this TDS range still might have bacteria and viruses which are responsible for water borne diseases so in the case UV water purifiers are recommended.

Acceptable TDS for drinking water in India

If TDS is greater than 300mg/L you can go for RO water purifiers but if the TDS is less than 300mg/L there is no need to buy RO water purifier, you will only need to filter out some organic and inorganic impurities of size that can be easily filtered out by UF filter, and kill bacteria that you can do with UV chamber, so UF+UV is the best combination for TDS around 300mg/L.

What to do if the TDS is more than 300mg/L in Drinking water?

If the TDS is more than 300mg/L you can go for RO or UF water purifiers but if you have TDS more than 500ppm then you must go for Reverse Osmosis (RO) water purifier, but remember if you buy RO purifier it must have a TDS controller or a mineral cartridge in it, so that you are not drinking mineral-less water because RO also filters out the essential minerals present in water, TDS controller and mineral cartridge helps in maintaining the minerals in drinking water.

And TDS should not be very low also, both low TDS and high TDS are hazardous to health, make sure when you test TDS in your filtered water sample it should come out to be between 100mg/L to 300mg/L.