When it comes to drinking water, most people focus on whether it is clean, clear, and free from visible impurities. But there’s another important factor that often goes unnoticed—TDS, or Total Dissolved Solids. If you’ve ever heard someone ask, “Is high TDS water bad for health?”, the answer isn’t a simple yes or no.
The TDS level of water tells us how many minerals, salts, and other dissolved substances it contains. While some of these minerals are essential for good health, excessive or harmful substances can pose risks. In this detailed guide, we’ll explore:
- What TDS means and how it’s measured
- Recommended safe TDS ranges for drinking water
- The health effects of both low and high TDS
- How taste, odour, and appearance are linked to TDS
- Methods to test and treat high TDS water
Understanding TDS in Drinking Water
TDS (Total Dissolved Solids) refers to the combined content of all inorganic and organic substances dissolved in water. These include:
- Minerals: Calcium, magnesium, potassium, sodium
- Salts: Chlorides, sulfates, bicarbonates
- Metals: Iron, copper, manganese (in trace amounts)
- Possible Contaminants: Lead, arsenic, nitrates (harmful if present)
TDS is measured in milligrams per litre (mg/L) or parts per million (ppm). A higher TDS number doesn’t automatically mean unsafe water—it depends on what those dissolved solids are.
For example:
- Natural spring water often has a higher TDS due to beneficial minerals.
- Industrial wastewater can also have high TDS but may contain toxic elements.
Safe TDS Levels: Global & Indian Standards
Health organisations and water quality boards have set guidelines for acceptable TDS levels.
| TDS Level (mg/L) | Water Quality Rating | Taste Expectation |
|---|---|---|
| 0 – 150 | Excellent (may taste flat if too low) | Fresh, clean, but possibly bland |
| 150 – 300 | Ideal Range | Pleasant, mineral-balanced |
| 300 – 600 | Good | Slight mineral taste |
| 600 – 900 | Fair | Noticeable taste changes |
| 900 – 1200 | Poor | Salty or metallic |
| Above 1200 | Unacceptable | Often unpleasant |
WHO (World Health Organization) Guidelines
- Water tastes best when TDS is between 300–600 mg/L.
- Above 1000 mg/L, water is generally unpalatable and may stain pipes.
BIS (Bureau of Indian Standards) Guidelines
- Acceptable limit: Up to 500 mg/L for drinking water.
- Beyond 500 mg/L, water requires treatment to be safe and palatable.
EPA (U.S. Environmental Protection Agency)
- 500 mg/L is set as a secondary standard (for taste and appearance, not enforceable by law).
Why TDS Matters for Health
TDS levels affect health in both direct and indirect ways. The impact depends on whether the dissolved solids are beneficial or harmful.
Potential Health Benefits of Moderate TDS
When water contains minerals like calcium and magnesium in safe amounts, it can:
- Support bone strength
- Improve heart health
- Aid muscle function and digestion
- Help maintain electrolyte balance
In fact, studies suggest that people drinking moderately hard water (rich in minerals) may have a lower risk of cardiovascular disease.
Health Risks of High TDS Water
The danger arises when high TDS comes from harmful contaminants rather than healthy minerals.
- Gastrointestinal Problems
- High sulfate levels (>250 mg/L) can cause diarrhoea or stomach cramps.
- Excess magnesium can also lead to laxative effects.
- Kidney Stones & Metabolic Stress
- Very hard water (high in calcium carbonate) may contribute to kidney stone formation over long periods.
- Toxic Metal Exposure
- Elevated TDS could indicate presence of lead, arsenic, or nitrates—all dangerous for health even in small quantities.
- Dehydration Risks
- If water tastes unpleasant, people may drink less, leading to dehydration, fatigue, and poor concentration.
High TDS and Taste Quality
TDS is not just about health—it’s also about taste, odour, and clarity.
- Fresh taste: 150–300 mg/L
- Slightly mineral taste: 300–600 mg/L
- Salty or bitter taste: 600+ mg/L
- Metallic taste: High iron or copper content
Unpleasant taste or smell can discourage water consumption, affecting hydration levels and overall wellness.
How to Check TDS in Your Water
1. Using a Digital TDS Meter
- Simple to use and gives instant readings in ppm.
- Does not identify which solids are present—only the total quantity.
2. Laboratory Water Testing
- More accurate and detailed.
- Identifies specific minerals and harmful contaminants.
How to Reduce High TDS in Water
If your water’s TDS is above safe limits, treatment is necessary. Here are the most effective methods:
1. Reverse Osmosis (RO) Systems
- Removes up to 95–99% of dissolved solids.
- Often paired with a mineral cartridge to restore essential minerals.
2. Nanofiltration
- Targets hardness-causing salts and certain contaminants while keeping some minerals.
3. Ion Exchange
- Softens water by swapping calcium and magnesium ions with sodium or potassium.
4. Distillation
- Boils water into steam, leaving dissolved solids behind, then condenses it back.
Recommended TDS Ranges for Specific Uses
- Drinking Water: 150–300 mg/L (ideal balance of taste and minerals)
- Cooking: 200–500 mg/L (flavours develop well)
- Aquariums: Depends on fish species; often 150–400 mg/L
- Industrial Use: Varies; high TDS can cause scaling and corrosion in machinery
Key Takeaways
- Not all high TDS water is bad—it depends on what makes up those dissolved solids.
- Moderate mineral content can be good for health, but excess harmful substances must be avoided.
- WHO, BIS, and EPA recommend keeping drinking water TDS below 500 mg/L.
- Testing is essential to know whether your water needs treatment.
- Reverse osmosis is the most reliable solution for reducing TDS to safe levels.
Final Thoughts
High TDS water can be both a friend and a foe. If the extra solids are beneficial minerals, your body can gain from them. But if they include toxic metals or excess salts, they can harm your health in the long run. The safest way forward is to test your water regularly, follow recommended TDS limits, and use the right filtration system when needed.
For expert water testing and tailored filtration solutions:
📞 Call ROSP: +91-9560654995
📧 Email: info@roservicepoint.com
