How to calculate tds of water

What is TDS, and Why Does It Matter?

TDS is the first thing you probably hear when talking about the quality of water. It’s also one of the most important parameters considered when looking to buy a water purifier. The water we drink today in many places across India, is not free from TDS. But what is TDS you ask? 

TDS is the total dissolved solids and indicates the total amount of organic and inorganic content in the water. Calcium, magnesium, potassium, sodium, nitrates, chlorides, carbonates, and sulfates are some of the inorganic salts that can be found in the water. These end up in water either naturally or as a result of human activities like agriculture, and industries. While some of these minerals are not harmful and can be consumed without worrying, other types of contaminants like lead, arsenic, fluoride, etc, can directly impact our health.

Understanding TDS and Its Impact

TDS is typically measured in parts per million (ppm) or milligrams per liter (mg/L). The World Health Organization (WHO) recommends keeping TDS levels below 300 mg/L for drinking water.

TDS Level (mg/L)	Water Quality
Less than 300	Excellent
300 - 600	Good
600 - 900	Fair
900 - 1200	Poor
Above 1200	Unacceptable

A high TDS can mean:

• Hard Water -  High calcium and magnesium content in water can make it hard, This results in buildup of scales in pipes and fixtures reducing their efficiency and life.
• Bad Taste and odour - Due to high mineral content, water with high tds can taste metallic and smell unpleasant.
• Health Concerns - Minerals like arsenic, mercury, and lead pose health hazards when consumed in the long run.

Methods to Calculate TDS of Water

• Using TDS Meters
• TDS meters measure the amount of dissolved solids in water by checking its conductivity. Higher the tds, higher is the meter’s conductivity. The tds levels are shown in parts per million (ppm) units. 0-50 ppm is an ideal tds value.
• Manual Calculation (Gravimetric Method)
• If you prefer a more hands-on approach, TDS can manually be measured using the gravimetric method:

1. Evaporate a measured amount of water until only the solids are left.
2. Weigh the leftover solids.
3. Use the formula:
   TDS = (residue weight in mg) ÷ (volume of water in L)

Home Testing for TDS

While the above methods may prove cumbersome, here are some simple methods you can try at home to measure tds at home:

1. Using TDS Test Strips
   TDS test strips are one of the easiest ways to check the dissolved solids in your water. All you need to do is dip the strip into a glass of water, wait for a few seconds, and then compare the color change on the strip to the chart provided with the kit. The color will give you an estimate of your water’s TDS level. 
2. Basic Water Testers
   Basic water testing kits with several types of strips that can measure not only TDS but also pH levels, hardness, and other factors are widely available and can be used to check tds levels. Just follow the instructions, and within minutes, you can see the results.

If you don’t have a TDS meter or strips on hand, there are still some less scientific but useful ways to know if your water’s TDS levels are high:

• Water Clarity: If your water looks cloudy or has particles floating in it, it might have high TDS. 
• Taste: Water with very high TDS usually tastes metallic. 
• Hard Water Signs: If you notice white spots on your dishes or mineral buildup in your appliances, it could mean that the tds levels in your water are high.

While these methods are not 100% accurate, they can help you decide if further testing is needed.

How to Reduce TDS in Water

If your water has high TDSlevels, here are some effective ways to lower it:

1. Reverse Osmosis (RO): RO filtration works on the principle of Reverse Osmosis and removes up to 99% of TDS by forcing water through a membrane that blocks dissolved solids.

1. Distillation: Boiling water and condensing the steam leaves most solids behind, though it’s a slow and energy-consuming method.
2. Deionization (DI): This method uses ion exchange to remove charged particles like calcium and sodium, reducing TDS.
3. Water Softeners: Primarily used for hard water, these reduce minerals like calcium and magnesium, helping to lower TDS slightly.

For most homes, an RO system is the best choice for significantly lowering TDS.

 

FAQs

 

1. How can I reduce TDS in my water?
   If your water has a high TDS level, you can reduce it using methods like reverse osmosis (RO) filtration, deionization, or distillation. These processes help remove the dissolved solids, providing you with cleaner water.

 

2. Can high TDS water be harmful?
   High TDS levels don’t always indicate a health risk, but water with excessive TDS might contain harmful contaminants like heavy metals, pesticides, or salts. It can also affect the taste of water and cause issues like water hardness, which leads to scaling on appliances and pipes.

 

3. What is the ideal TDS level for drinking water?
   The World Health Organization (WHO) recommends that drinking water should have a TDS level below 300 ppm. Levels between 300-600 ppm are generally acceptable, but anything above 900 ppm is considered poor and may need treatment before consumption.

 

4. Can boiling water reduce TDS?
   No, boiling water only kills bacteria and other microorganisms but does not reduce the TDS. It can actually concentrate the dissolved solids because water evaporates but the solids remain.
5. Does low TDS mean the water is better?
   Not necessarily. Very low TDS levels could indicate the absence of essential minerals like calcium and magnesium, which are important for health. Water with extremely low TDS may also taste flat or bland.