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.

Why Do You Need to Check TDS?

By measuring TDS levels in the water, you will be able to make sure whether the water you are drinking is pure or impure. Do you know what is the maximum contamination level advised by the EPA Secondary Regulations? The maximum TDS level of drinking water is 500mg/liter. Whether you get your water from the nearby lake or a tank, you must make sure that it meets this mentioned level. If you see that the level is exceeding 500mg/liter, we suggest that you do not drink that water.

TDS – acceptable values

Bureau of Indian Standards (BIS) has specified the value of TDS that drinking water should contain.

According to BIS, the TDS value up to 500 mg / Ltr is acceptable in drinking water. If the TDS level is higher than this, it is not safe to drink.

Please have a look at the table below to understand the acceptable TDS value in drinking water.

TDS (mg/ltr)Rating
Less than 300Excellent
300 – 500Good – Acceptable for human consumption
500 – 900Not good – Should not be consumed.
900 – 1200Poor – Unfit for human consumption.
Above 1200Unacceptable

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How To Calculate Water TDS At Home?

There are various methods to check water TDS at home. Here we’ll be discussing the 2 most crucial and widely accepted methods to check water TDS at home, which are

  1. Using Digital TDS meter
  2. Using Filter Paper & Scale

1. How To Check Water TDS Using Digital TDS Meter?

Digital meter is one of the simplest methods to check water TDS, and it is a widely accepted method globally, and the main reason for this is, it does not require mathematical calculation to get an accurate reading. A digital TDS meter brings instant results.

Steps To Follow While Calculating Water TDS Using Digital TDS Meter

  • Remove the protective cap of the Digital TDS meter and switch it “ON”
  • Dip the Digital TDS meter in the water up to the maximum immersion level (Marking is used to indicating the immersion level in the Digital TDS meter)
  • Stir the Digital TDS meter to remove the air bubbles if present in the water. Stirring will remove the air bubble from the water
  • Now, wait for 10-15 seconds after placing the Digital TDS meter inside the water to measure the TDS level of the water
  • Few brands digital TDS meters bring the reading by multiplying it by 10, but in some TDS meters, you need to multiply the value by 10
  • After calculating the TDS level of the water, shake off the excess water from the digital meter and replace the protective cap

Precaution needs To Be Taken While Using TDS Meter

There are few precaution which you need to take while measuring water TDS at your house using a digital TDS meter, and these are

  • Don’t dip the digital TDS meter beyond the maximum immersion level. Although a digital TDS meter is watertight, still you need to ensure that you have dipped the TDS meter only up to the maximum immersion level
  • Don’t explore the digital TDS meter directly in the sunlight

2. How To Check TDS Using Filter Paper & A Scale?

It is one of the conventional methods to check water TDS level, and methods need no equipment, but it needs few apparatus. Below we have listed steps that need to be followed for measuring water TDS using Filter paper & a Scale.

But before you start discussing crucial steps, let’s discuss which apparatus are needed for measuring water TDS using Filter Paper & a Scale

Required Apparatus

  • A clean & sanitized glass container
  • Water sample for TDS determination
  • Filter paper or Layers of Cotton
  • Evaporating dish
  • A sterile stirring stick
  • A pipette to take 50ml water sample
  • A weighing machine or scale

Steps To Follow For Measuring Water TDS Using Filter Paper & A Scale

Below we have listed complete steps that will help you in measuring water TDS levels.

  • Weigh The Evaporating Dish: Measure the evaporating dish using a weighing machine and note the reading in mg. Before you measure the weight of the evaporating, ensure that the dish is completely empty, dry, and free from any extraneous matter
  • Stir The Water Sample: Stir the water sample vigorously so that the matter present in the water can be dispersed equally throughout the water sample
  • Collect The Water Sample: Take a 50ml water sample using a pipette. While taking the water sample, ensure that no matters are settled down on the container bottom. If the matter is settled down on the container’s bottom, stir the water sample and then take a sample. Because if the matter is not dispersed equally, then reading will not be accurate
  • Extract The Filtrate: Now, pour the water sample into the container through the filter paper. Repeat this process at least 3 times to ensure that the matter is entirely collected in the filter paper and transfer to the evaporating dish
  • Weigh The Evaporating Dish With The Filtrate: Allow the present matter to dry completely, then weigh evaporating dish with extracted filtrate and note the reading in mg and calculate the TDS value
How do I reduce the TDS of water

TDS Level in Drinking Water – FAQs

Does a high TDS level always mean the water is unfit for consumption?

Always remember that a high TDS does not always necessarily mean that the water is unsafe for consumption. Sometimes it means that it may be a bit odd in terms of taste, color, or smell. Ideally, the TDS for drinking water must be below 300mg/liter and the maximum limit that is considered safe is 500mg/liter. But it should not be less than 100mg/liter for perfect health.

How to reduce the TDS level in drinking water?

Water purifiers that come with reverse osmosis (RO) technology are a great solution to reduce high TDS levels in the water. These purifiers are built with cutting-edge technology to ensure that the TDs levels in water are reduced and that the water is safe for drinking. If you are planning to buy one, then you can check the latest range of RO water purifiers.