Have you ever noticed that water from different places tastes different? Sometimes it’s sweet, sometimes salty, and sometimes it even has a metallic aftertaste. This difference often comes down to TDS—Total Dissolved Solids in the water.
Most people drink water every day without knowing whether their water has too much or too little TDS. The reality is that TDS affects not only taste but also your health and household appliances. Measuring it helps you decide whether you need purification and what kind of purifier works best.
Key Takeaways
- TDS (Total Dissolved Solids) measures all minerals, salts, and impurities dissolved in water.
- WHO suggests safe TDS levels for drinking water should ideally be below 300 ppm.
- Low TDS water may taste flat and lack essential minerals.
- High TDS water may taste salty, bitter, or metallic and could harm health over time.
- Measuring TDS with a meter helps you choose the right purifier (RO, UV, or UF).
What Does TDS Mean in Water?
TDS = Total Dissolved Solids.
It refers to the total amount of organic and inorganic substances dissolved in water. These include:
- Minerals (calcium, magnesium, potassium)
- Salts (sodium, bicarbonates, chlorides, sulfates)
- Metals (iron, lead, arsenic)
- Small organic matter
TDS is expressed in parts per million (ppm) or milligrams per liter (mg/L).
What Contributes to TDS in Water?
Several factors add dissolved solids to water:
- Natural sources – Rocks and soil release minerals like calcium and magnesium.
- Pipelines – Rust, corrosion, or sediments increase TDS.
- Industrial pollution – Chemicals and heavy metals enter groundwater.
- Fertilizers & pesticides – Agricultural runoff raises nitrate levels.
Why Should You Measure TDS in Water?
1. Does TDS Affect Water Taste?
Yes. TDS is one of the biggest factors in how water tastes.
- Low TDS (<100 ppm) → Flat or bland taste.
- Moderate TDS (150–300 ppm) → Fresh and pleasant taste.
- High TDS (>500 ppm) → Salty, metallic, or bitter taste.
2. How Does TDS Impact Health?
- Very Low TDS (<50 ppm): Lacks essential minerals. Long-term drinking may cause deficiencies.
- High TDS (>500 ppm): May contain harmful contaminants like arsenic, nitrates, or lead. Can cause kidney stress and other health issues【WHO, 2022】.
- Optimal TDS: Between 150–300 ppm provides a balance of safety and good taste.
3. Does TDS Affect Household Appliances?
Yes. High TDS leads to scale deposits in kettles, geysers, washing machines, and pipes. This reduces appliance life and efficiency.
Fact: Hard water with high TDS can increase energy consumption in water heaters by up to 29%【US Department of Energy, 2021】.
What Is the Ideal TDS Level in Drinking Water?
Here’s a quick reference:
| TDS Level (ppm) | Water Quality | Suitability |
|---|---|---|
| 0–50 | Very Low | Not suitable (lacks minerals) |
| 50–150 | Excellent | Best for drinking |
| 150–300 | Good | Safe & pleasant taste |
| 300–500 | Fair | Acceptable in some cases |
| 500–900 | Poor | Not suitable for drinking |
| 900–1200 | Very Poor | Unsafe |
| Above 1200 | Unfit | Should not be consumed |
How Can You Measure TDS in Water?
1. Digital TDS Meter
- Handheld device that shows TDS instantly.
- Affordable and easy to use.
- Accuracy: ±2%.
2. Laboratory Testing
- Most accurate.
- Tests for individual minerals, salts, and chemicals.
- Recommended if you suspect contamination.
3. Electrical Conductivity (EC) Method
- TDS is estimated based on water’s ability to conduct electricity.
- Used in large-scale water plants.
What Are the Effects of High TDS Water?
High TDS water is not always harmful, but it depends on what’s dissolved.
- Calcium & Magnesium: Cause scaling (hard water).
- Iron: Metallic taste, reddish stains.
- Chlorides: Salty taste.
- Nitrates & Arsenic: Health risks such as kidney problems or cancer (long-term exposure).
Stat Insight: Around 2 billion people globally drink water contaminated with unsafe levels of TDS and pollutants【UNICEF, 2021】.
What Are the Effects of Low TDS Water?
Low TDS may sound good, but it’s not always healthy.
- Can taste flat or acidic.
- Lacks essential minerals (calcium, magnesium, potassium).
- Long-term consumption may cause mineral deficiencies.
WHO Study: Drinking very low-mineral water (below 30 ppm) may increase the risk of cardiovascular disease due to lack of calcium and magnesium【WHO, 2019】.
How Is TDS Different From Water Hardness?
Many people confuse the two.
| TDS | Hardness |
|---|---|
| Measures all dissolved solids (minerals, salts, metals) | Measures only calcium and magnesium salts |
| Expressed in ppm (mg/L) | Expressed in ppm or degrees of hardness |
| Includes beneficial & harmful substances | Only indicates hardness of water |
| High TDS ≠ always hard water | High hardness = part of TDS |
Which Water Purifier Should You Use Based on TDS?
| TDS Level (ppm) | Recommended Purifier |
|---|---|
| Below 200 | UV or UF |
| 200–500 | RO + UV |
| 500–1000 | RO + UV + UF |
| Above 1000 | Advanced RO with TDS controller |
Tip: If TDS is too high (>1000 ppm), RO is the only reliable method to bring it to safe levels.
Can TDS Alone Tell You If Water Is Safe?
No. TDS only measures quantity of dissolved solids, not their type. For example:
- High TDS with calcium may be safe.
- Low TDS with arsenic or lead is unsafe.
That’s why water testing should combine TDS measurement + lab analysis for accurate results.
Common Myths About TDS
- Myth 1: Lower TDS is always better.
Truth: Very low TDS water can harm health. - Myth 2: TDS tells you everything about water quality.
Truth: TDS doesn’t identify individual contaminants. - Myth 3: All high TDS water is harmful.
Truth: High TDS with natural minerals (like spring water) may still be safe.
How to Reduce TDS in Drinking Water?
- Reverse Osmosis (RO): Best method for high TDS water.
- Distillation: Effective but energy-intensive.
- Deionization: Removes dissolved salts but usually combined with other methods.
Conclusion
TDS in water is not just a number—it’s the measure of what you and your family consume every day. Too high, and you risk salty taste, scaling, and possible health hazards. Too low, and you miss out on essential minerals.
The ideal TDS for drinking water is between 150–300 ppm, where safety, taste, and nutrition meet. By measuring TDS regularly and choosing the right purifier, you can ensure safe and healthy water for your family.
So the next time someone asks, “Why does my water taste funny?”—you’ll know the answer lies in TDS.
Hasan Al Sarker is a Reverse Osmosis Specialist. He has worked for many years to ensure safe drinking water for all. His research paper has been published in several journals, including Issue, Medium, and Slideshare. He is recognized as a water doctor among specialists though he did not attend medical college.
Besides working as a researcher of reverse osmosis technology, he is also very fancy with the kitchen and cooking. His guides are reading thousands of people every day. As a head of content, he is responsible for all the published articles at RO System Reviews.