How to Check TDS Level & Ideal TDS for Drinking Water
Have you been hearing a lot about the TDS level in drinking water?
You must have.
Because that is what all the water purifier companies are talking about. That is one measure even consumers are talking about the most.
But, what exactly is this “TDS” and what is the ideal TDS for drinking water?
If you have no clue about what is the meaning of TDS in water, then you must read this post.
This post will provide you with all the details about
- What is the TDS level in water?
- How you can measure the TDS level?
- What is the ideal TDS level of drinking water?
TDS of Water Full Form
The full form of TDS in drinking water is “Total Dissolved Solids”.
What is TDS Level?
TDS level of water is the measure of all inorganic and organic substances that are dissolved in water.
The most 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 healthy, but when the level becomes too much, it is a cause for worry.
Most common constituents of TDS levels, like calcium, magnesium, etc., are generally harmless. But heavy metals like lead, mercury, arsenic, and fluoride can be really dangerous for your health.
Why Do You Need to Check TDS Level?
A study conducted by IIT Kharagpur revealed that almost 20% of India’s total land area has toxic levels of arsenic in its groundwater.
A significant number of Indians are drinking toxic water.
This is also evident from the data released by the Ministry of Jal Shakti in the reply to a question asked in Rajya Sabha on 1st August 2022. It was revealed that:
- Arsenic was found in around 209 districts in 25 states and UTs
- Uranium was found in parts of 152 districts across 18 states
- Lead was found in parts of 176 districts in 21 states.
- Iron was found in parts of 491 districts in 29 states and UTs
- Cadmium in parts of 29 districts in 11 states
- Chromium in parts of 62 districts in 16 states
Although TDS level does not tell you anything about the presence or absence of any of the contaminants that make up the TDS level.
But it gives you an initial idea of the overall quality of your drinking water.
And the best part is measuring the TDS level is very easy, as you’ll see below. So, there are no excuses for not knowing the TDS level of the water your family drinks.
A high TDS level (above 500 mg/l) indicates that the water quality is not good and you should not drink such water without purification.
Apart from the TDS level, there are around 50 other individual contaminants.
A thorough investigation of drinking water quality is only possible at a drinking water testing lab.
How to Check the TDS Level of Water at Home?
There are several methods for measuring the TDS level of water.
Below we have provided step-by-step tutorials on how to find the TDS level of water at home with and without using a TDS meter.
Method 1: Using Digital TDS Meter
The easiest way to find the TDS level of water at home is by using a digital TDS meter.
A digital TDS meter is an affordable, small, and easy-to-use device.
Use a digital TDS meter to check the performance of your RO water purifier, test the water quality, check for hardness, and ensure that you are drinking clean water.
Digital TDS meters are widely available in all the leading online stores in India and you can easily buy a quality Digital TDS Meter from Amazon.in for a few hundred rupees.
Here is how you can use a digital TDS meter to measure the TDS Level of water:
- 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 inches).
- 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 the ‘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.
Watch this video on how to measure the TDS level in drinking water.
Precaution:
- Do not dip the meter beyond 2 inches because the meter is not watertight.
- Do not store the meter in places of high temperature or where direct sunlight comes.
Method 2: Using Filter Paper and a Scale
This conventional method was used before the invention of digital TDS meters.
We do not suggest using this method now as it requires a lot of time and effort. The final results are also not very highly reliable and the whole process is prone to error.
What are the things that you need?
- A sterilized beaker.
- A sample of water (tap water or rainwater) 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 empty, and 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 the beaker 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 them to the evaporating dish.
Step 6 – Wait for the filtrate (particles) to completely dry.
Step 7 – Once the filtrate on the evaporating dish is dry, weigh 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 will be 50. The final value of the dissolved solid is going to be measured in mg/L.
Precaution:
- Carefully weigh the evaporating dish and also, the weight of the evaporating dish with the filtrate.
- Wait for the filtrate or particles to completely dry before proceeding.
Most people often confuse the TDS level with water hardness. High TDS levels do not always mean that the water is hard. If you want to find out the hardness level of water then you should perform a water hardness test.
What is the Ideal TDS Level 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 is not available.
No health-based guideline value is proposed for the ideal TDS of drinking water. Because TDS in water can be high because of many factors, in areas where the TDS content of the water supply is very high, the individual constituents should be identified.
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 about its TDS level as follows:
| TDS Level (mg/l) | Rating |
|---|---|
| Less than 300 | Excellent |
| 300-600 | Good |
| 600-900 | Fair |
| 900-1200 | Poor |
| Above 1200 | Unacceptable |
What is the maximum TDS level advised by the Indian Authorities?
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 water quality standards also mention 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.
Whether you get your water from a borewell, water tanker, or municipal tap, you must make sure that it meets the BIS water quality standards. If your drinking water’s TDS level exceeds 500 mg/L, we suggest that you do not drink that water.
Minimum TDS Level for Drinking Water
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 the TDS level to a very low value also affects the pH level of the water, which BIS specifies should be in the range of 6.5-8.5. Water with very low TDS will taste dull.
There is no official minimum TDS level for drinking water, but a TDS of at least 50-150 ppm is the accepted minimum level.
| TDS Level (mg/l) | Reasons for Acceptability/Non-acceptance |
|---|---|
| Less than 50 | Safe but not ideal. You may find the water tasteless as water with such a low TDS level does not contain the essential minerals. |
| 50-150 | Acceptable. However, a TDS level in the range of 80-150 is considered ideal. If you are using an RO water purifier then make sure the TDS level of purified water is not below 80 mg/L. |
| 150-250 | Not acceptable. Use an RO water purifier with a TDS controller or mineralizer. |
| 250-350 | Acceptable. Most urban Indian homes have access to water in this TDS range. |
| 350-500 | Acceptable. As per the BIS guidelines, a TDS level below 500 mg/L is acceptable. |
| 500-900 | Not acceptable. Use an RO water purifier with a TDS controller or mineralizer. |
| 900-1200 | Not acceptable. Use an RO water purifier with a TDS controller or mineralizer. |
| 1200-2000 | Not acceptable and not fit for drinking. Choose a RO water purifier that can purify water with up to 2000 mg/L. |
| Above 2000 | Do not drink. Most home water purifiers can’t purify water with a TDS level over 2000 mg/L. |
Check out the following link if you would like to learn more about how Total Dissolved Solids come in water and what is the effect of low or high TDS on your health.
TDS Level in Drinking Water – FAQs
Always remember that a high TDS does not necessarily mean that the water is unsafe for consumption. Sometimes it may be a bit odd in terms of taste, color, or smell. Ideally, the TDS for drinking water should be below 300 mg/liter and the maximum limit that is considered safe is 500 mg/liter.
If you are eager to find out how good or bad your drinking water is, then you should get your drinking water tested.
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.
Click to read: Can Water Softeners Lower the TDS Level of Water?
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 of any other way to measure TDS levels, please feel free to comment.
Very helpful information. Thank you.🙂🙏🏽
Thank you for sharing good info. Digital Water Meters is a device used to measure the amount of water consumed in a building.
Super information, thank you.
Please tell me do I need to check the tds level of my ro filtered water? If yes then how often and how much should it be ?
Yes, you should keep a check on the TDS level of RO purified water. There is no thumb rule for how often do you need to check. You can check it on a monthly basis. Please refer to the table above for ideal TDS level of RO purified water.
the TDs of my ro is 156*10 according to my TDS meter , does it need servicing ?
Everyone loves it when people come together and share ideas.
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Keep up the amazing work!
300-600
Hello… what is the frequency of testing ro water for tds?
TDS of my house water is within 200 to 230 It is correct. Give correct information please……Thank You 👍
TDS 25 क्या पीने का पानी ठीक है कृपया बताएं
300
If tds is 530, by boiling the water will the tds come down further? What r the advantages or disadvantages of boiling water?
Boiling water does not remove dissolved solids or lower the TDS. Boiling only kills disease causing micro-organisms but does not remove any dissolved or suspended impurities. Boiling can not remove:
What is the time duration for changing water filter? Which is fitted outside the RO (a single fitted filter)
Hello,
We believe you are asking about changing the sediment filter. Sediment filter should be changed at least once a year. But if the water coming to your home is very muddy you should change it earlier. Because if the sediment filter is not replaced on time the dirt and slit will reach the RO membrane which will reduce the life of RO membrane and may affect the purification quality as well.