Have you been hearing a lot about TDS level in drinking water? You must have because that is what all the water purifier companies are talking about. That is one feature that even consumers are going after. But, what exactly is this “TDS”? If you have no clue, let us tell you everything about it, along with how you can measure it.
Table of Contents
- What does TDS really mean?
- How to check the TDS level in water?
- How can you reduce TDS levels in drinking water?
What does TDS really mean?
TDS stands for “Total Dissolved Solids”and it is the measure of all inorganic and organic substances that are dissolved in water. The very common inorganic substances that are found in water are magnesium, calcium and potassium. To a certain degree, the presence of these minerals in the water is actually healthy, but when the level becomes too much, it is a cause of worry.
Why do you need to check TDS?
By measuring TDS in 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 in 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 1000mg/liter, we suggest that you do not drink that water.
What is the Ideal TDS of Drinking Water?
World Health Organization (WHO) report on TDS in drinking water points out that reliable data on possible health effects associated with TDS in drinking-water are not available.
The Bureau of Indian Standards (BIS) has set the acceptable limit of TDS in drinking water at 500 mg/L. However, the standard also mentions that in case no alternative source of drinking water is available, then this acceptable limit can be relaxed to 2,000 mg/L. The BIS report also mentions that if the drinking water TDS is higher than 500 mg/L then this may result in a decrease in palatability (acceptable taste) and may cause gastrointestinal irritation.
This acceptable TDS limit applies to only normal fresh water, if the water contains toxic impurities like arsenic or fluoride then other special BIS standards will be applicable.
It is important to note that some of the dissolved minerals in water are useful for human health and therefore very low or zero TDS is also not recommended. Reducing TDS level to a very low value also affects the Ph of the water, which BIS specifies should be in the range 6.5-8.5. Water with very low TDS will taste dull. There is no official lower limit, but TDS of at least 80 ppm is the accepted minimum level.
The presence of dissolved solids in water may affect its taste. The palatability (acceptable taste) of drinking water has been rated by panels of tasters in relation to its TDS level as follows:
|Chart for TDS of Drinking Water According to Taste|
|TDS level (mg/l)||Rating|
|Less than 300||Excellent|
How to check the TDS level in water?
There are a number of methods by which you can measure TDS level in water. We have compiled some of the most common methods that you can use in your home to know whether or not you are drinking safe water.
Method 1: Using Digital TDS Meter
This is a state-of-the-art digital TDS meter tester that you can use to check the performance of your water filter, test the quality of filter water, check for hardness and make sure that you are drinking clean water. Digital TDS meters are widely available on all the leading online stores in India and you can easily buy a quality Digital TDS Meter in few hundred rupees.
#Step 1–Measure the temperature of the water. Follow the given steps for that:
• Switch the meter on.
• Press the TEMP button. The temperature will be displayed in Celsius only.
• To return to TDS mode, press TEMP button again.
#Step 2 – Measure the TDS level. To do that, follow the given instructions:
• Remove the protective cap.
• Turn the TDS meter on. You will find the ON/OFF switch is on the panel.
• Immerse the meter into the water up to the maximum immersion level (2 inch).
• Gently stir the meter to dislodge any air bubbles.
• Wait till the reading stabilizes (approximately, 10 seconds).
• Press the HOLD button and take it out of the water to view the reading.
• If the meter displays ‘x10’ symbol, it means that you have to multiply the reading by 10.
• After use, shake off the excess water from your meter and replace the cap.
1. Do not dip the meter beyond 2 inch because the meter is not water tight.
2. Do not store the meter in places of high temperature or where direct sunlight comes.
Method 2: Using Filter Paper and a Scale
This is a conventional method that you can easily use in your home to measure the level of TDS in your drinking water. For this, you do not need any TDS meter, but very simple everyday things.
What are the things that you need?
• A sterilized beaker.
• A sample of water (tap water or rain water) in the beaker.
• Filter paper.
• An evaporating dish.
• A stirring stick.
• A pipette that is large enough to collect a water sample of 50ml.
• A scale to measure.
Now, follow the instructions:
#Step 1 – Weigh the evaporating dish in milligrams and make sure that the dish is completely empty, free from any kind of particles. Note this measurement as “A” and come back to it after all the steps have been completed.
#Step 2 – Take the stirring stick and vigorously stir the sample of water in the sterilized beaker. You need to agitate the liquid so that the particulate matter present in matter gets evenly distributed.
#Step 3 – Take the pipette and collect 50ml of the stirred water. Please note that even while collecting the water, you have to continue stirring the liquid.
#Step 4 – Extract water from the pipette and pass it on to the filter paper 3 times. There will be some sediment left behind in the filter paper.
#Step 5 – If you see any particles in the filter paper, transfer it to the evaporating dish.
#Step 6 – Wait for the filtrate (particles) to complete dry.
#Step 7 – Once the filtrate on the evaporating dish is dry, weight the evaporating dish again (with the filtrate) and call it “B”.
#Step 8 – Measure the TDS level by subtracting B from A.
To check TDS level, use the formula: TDS = [(A-B)*1000]/ml
In this formula, A stands for the weight of the evaporating dish + filtrate and B stands for the weight of the evaporating dish. Since 50ml was the quantity that you took in the pipette, the value of “ml” in this case is going to be 50. The final value of the dissolved solid is going to be measured in mg/L.
1. Carefully weigh the evaporating dish and also, the weight of the evaporating dish with the filtrate.
2. Wait for the filtrate or particles to completely dry before proceeding.
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 maximum 500mg/liter.
How can you reduce TDS levels in drinking water?
Water purifiers that come with reverse osmosis (RO) technology are a great solution to tackle high TDS levels in 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.
With the help of a TDS meter, you can even check the longevity and functionality of the RO membrane and replace it, if need be.
Share this information with your friends and family to equip them with the knowledge needed for checking the TDS level in drinking water. If you know any other way to measure TDS levels, please feel free to comment.
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