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What is a TDS Meter? – How do you check the TDS level in the water?

Irrespective of the type of water purifier you have at home, its proper maintenance is required. The absence of this can cause your water filters to deteriorate, thereby affecting the TDS. Such harmful changes can be noted with the help of a TDS meter.

In a way, a TDS meter is an easy-to-use appliance that can be used to check the TDS of the water. While it does not measure the contaminants, it helps check the total dissolved solids in the water.

If you find that intriguing, read along, as we have a lot more in store with the following article as far as TDS meters are concerned.

What is TDS?

TDS is nothing but a mixture of dissolved solids like potassium, calcium, carbonates, fluorides, magnesium, and many more. Water sources like groundwater, river, ponds and lakes contain heavy toxic metals like mercury, lead, and arsenic. These toxic chemicals are extremely hazardous to health. Thus you will require a good water purifier if the water supply in your area has high TDS.


How to Measure the TDS level in the water?

The TDS level in the water can be checked in the below three ways.

1. Digital TDS Meter

The measurement of TDS through this meter is one of the most straightforward and uncomplicated methods of the three. In this method, you will not have to do the calculations implementing mathematical formulas nor have to take any readings. You get the results instantly. Some water purifiers come with inbuilt TDS meters to monitor the level often. They are measured in milligrams per liter (mg/liter) and are also called PPM (parts per million).

The TDS meters are available in any retail or medical store for a few bucks. The machines are available in numerous calibrations. TDS meter has a measurement reading range of 0 to 5000 PPM.

Method of TDS Meter measurement

  • First, you need to switch on the TDS meter.
  • Then press the TEMP button, where you will get a reading in degrees Celsius.
  • Return to the TDS mode by pressing the TEMP button again
  • Now remove the protective cap and turn on the meter
  • Immerse the TDS meter inside the water sample to the maximum level of 2 inches. A marking is present on the TDS meter to indicate this level
  • If any air bubble is present in the water, gently move the device to eliminate them
  • Wait for a minimum of 12 to 15 seconds to acquire a stable reading
  • Press the hold button and gently take it out from the water to view the reading
  • Some models of TDS meters come with an X10 symbol. In these cases, you have to multiply the reading by 10
  • After using the device, remove the additional water and again cover it with a protective cap


Precautions to take using TDS Meter

The TDS meter is not at all watertight. Hence you should not insert the machine below the maximum level. Also, remember to keep it in a cool place and not expose the equipment to direct sunlight.


2. Measurement through Weighing Scale and Filter Paper

This is one of the most conventional methods to measure the TDS level in the water. In this method, you will not require any apparatus.


  • Sterilized and clean glass beaker
  • Water sample
  • Evaporating dish
  • Filter paper
  • Sterile stirring stick
  • Pipette to collect 50 ml of water
  • Weighing scale

With the help of the weighing scale, measure the weight of the empty evaporating dish. Make sure that the dish is dry and free from any particles. Note down the reading of the dish in mg. Stir the water sample to make sure that the particulate matters distribute evenly in the water. Collect a water sample of 50 ml through the pipette. It would be best if you stirred the sample continuously to make sure that the matters did not settle at the bottom; otherwise, it would not give a precise reading.

Now pour the sample into another container via filter paper. Repeat this method three to four times to make sure that every particular matter is inside the filter paper. Now transfer the filtrate sample into the evaporating dish and dry the water completely. Measure the weight of the dish along with filtrate and note down the reading in mg.

The main formula for carrying out the measurement is

TDS= weight of the evaporating dish with filtrate- the weight of the empty dish X 1000


3. Method of Electrical Conductivity Meter

TDS contains both inorganic and organic salts. For this process, you will require a conductivity meter and sterilized glass beaker that should be dust-free. The meter operates by emitting an electric current into the water by measuring the resistance. These methods of electrical conductivity meters calculate the TDS level in the following ways.

  • Place the beaker on a flat surface and turn on the meter
  • Insert the lead measuring the TDS inside the water
  • The reading will start fluctuating before stabilizing
  • Note down the reading in Micro Siemens

Note that the lower the micro Siemens, the purer the water will be for consumption. The water’s TDS level should always be below 500, which is considered an ideal level for drinking purposes. You need to install RO water purifiers if the TDS level is more than 500 mg/liter. According to BIS, any water supply that has a TDS level of 1200 mg/liter is completely unacceptable for drinking purposes.



At the end of this write-up, we know everything about TDS and different ways to check the level as well. This measurement will assist you in making a decision about which water purifier should be installed in your home. Stay tuned to our blog for more information like this.

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