Water is one of the most vital resources for human survival. With increasing concerns about water quality and safety, more and more people are paying attention to technical terms like “TDS” (Total Dissolved Solids). One common question is: Is 25 TDS safe for drinking water? This article dives deep into the science, health implications, regulatory standards, and expert recommendations to help you understand whether water with 25 TDS is safe and suitable for daily consumption.
What is TDS in Drinking Water?
Total Dissolved Solids (TDS) refers to the amount of organic and inorganic substances dissolved in water. These substances include minerals, salts, metals, and ions like calcium, magnesium, sodium, potassium, bicarbonates, chlorides, and sulfates.
TDS is measured in milligrams per liter (mg/L) or parts per million (ppm). A TDS meter is commonly used to measure the level of dissolved solids in water, providing a quick indication of its quality.
Sources of TDS in Water
The TDS level in drinking water can come from various natural and human-made sources:
- Natural sources: rock erosion, weathering, mineral springs
- Municipal and industrial waste: chemicals, detergents, treatment by-products
- Agricultural runoff: fertilizers, pesticides
- Water treatment processes: reverse osmosis (RO), demineralization, distillation
WHO and BIS Guidelines for TDS Levels
Both the World Health Organization (WHO) and the Bureau of Indian Standards (BIS) provide guidelines for TDS levels in drinking water:
| TDS Level (mg/L) | Palatability Rating | Comment |
|---|---|---|
| < 50 | Very low | Not ideal for taste or mineral balance |
| 50 – 150 | Excellent | Optimal for taste and health |
| 150 – 250 | Good | Acceptable for most uses |
| 250 – 500 | Fair | May taste slightly mineralized |
| 500 – 1000 | Poor | Not preferred unless no alternative |
| > 1000 | Unacceptable | Not safe without treatment |
The BIS standard for acceptable TDS in drinking water is up to 500 mg/L, and the maximum permissible limit in the absence of an alternative is 2000 mg/L.
Is 25 TDS Safe for Drinking Water?
Technically, Yes — But It’s Not Ideal
Water with 25 TDS is technically safe to drink, meaning it does not pose an immediate health risk. However, “safe” does not necessarily mean “optimal.” Here’s why:
1. Lack of Essential Minerals
A TDS level of 25 indicates extremely low mineral content. While this may seem good from a purity standpoint, it can lead to:
- Loss of beneficial minerals like calcium, magnesium, and potassium
- Flat taste or lack of freshness
- Potential long-term health impacts from mineral deficiency
2. Taste and Palatability
Water with very low TDS tends to taste bland or slightly acidic, especially when stripped of natural minerals during processes like reverse osmosis or distillation.
3. Corrosiveness
Extremely low TDS water can be slightly corrosive, which may leach metals from pipes and fixtures, such as lead or copper, especially in older plumbing systems.
Health Implications of Drinking Water with 25 TDS
Short-Term
There are typically no immediate health hazards associated with drinking low-TDS water (including 25 TDS) for a short period. It is safe for hydration, cooking, and general use.
Long-Term
However, drinking water with ultra-low TDS levels over a long period may not provide enough essential minerals, which can be particularly problematic for:
- Infants and children who need calcium and magnesium for bone development
- Athletes and active individuals who lose electrolytes through sweat
- People with kidney or cardiovascular conditions that benefit from balanced mineral intake
Scientific studies suggest that demineralized water (like distilled or RO water with <50 TDS) may not support optimal health unless minerals are replenished through diet or remineralization.
Ideal TDS Level for Drinking Water
Most water quality experts agree that the ideal TDS level for drinking water falls between 50 to 150 ppm. This range:
- Maintains taste
- Retains beneficial minerals
- Avoids corrosiveness
- Ensures long-term health benefits
What Causes 25 TDS in Water?
Such a low TDS value typically results from:
1. Reverse Osmosis (RO) Filtration
RO systems are very effective at removing TDS, often reducing levels from 500+ ppm to under 50 ppm. Unless the system includes a remineralization filter, the output will be low-TDS water.
2. Distillation
Distilled water also shows extremely low TDS (approaching 0 ppm), as it removes all ions and particles.
3. Naturally Soft Water Sources
Some mountain springs or rainwater sources may naturally have very low TDS due to minimal contact with rocks or soil.
Should You Drink 25 TDS Water Every Day?
It Depends on Your Overall Diet
If you:
- Eat a balanced diet rich in fruits, vegetables, and whole grains
- Take mineral supplements
- Do not suffer from any chronic health conditions
Then drinking water with 25 TDS occasionally or even daily may not be harmful.
But if you:
- Have a mineral-deficient diet
- Rely heavily on water as a mineral source
- Are prone to electrolyte imbalances
Then long-term consumption of 25 TDS water is not advisable without adding a remineralizer or switching to a better-balanced source.
How to Increase TDS in RO Water (If Needed)
If your RO system consistently produces water around 25 TDS, and you want to increase it to a more optimal range (50–150), here are some ways to do so:
1. Use a Remineralization Filter
Install a post-RO cartridge containing calcium and magnesium to add minerals back into the water.
2. Add Himalayan Salt or Electrolyte Drops
You can naturally increase mineral content with just a pinch of Himalayan salt or a few electrolyte concentrate drops.
3. Blend RO Water with Tap Water (if safe)
Mixing a small amount of high-TDS water with RO water can improve taste and mineral content, assuming local tap water meets safety standards.
TDS and Water Purification: What’s the Balance?
In the effort to purify water, many RO systems remove more than just contaminants — they also remove essential minerals. The key is to balance purity with nutritional value. Ultra-pure water is excellent for lab work or batteries but not always for regular consumption.
Your goal should be to drink mineral-balanced water, not just “pure” water. Aim for water that is:
- Microbiologically safe
- Chemically free of harmful contaminants
- Nutritionally supportive with 50–150 ppm TDS
Alternatives to Low-TDS Water
If you’re concerned about your RO system producing excessively low TDS, consider these alternatives:
1. Mineral Water
Bottled mineral water naturally contains essential minerals and usually falls within the ideal TDS range.
2. Spring Water
Untreated spring water from safe sources often has moderate TDS levels and good taste.
3. UV + UF Water Purifiers
If your tap water is low in contaminants but still has high TDS, these systems can purify without stripping away all the minerals.
Final Verdict: Is 25 TDS Safe?
Yes, 25 TDS water is safe for drinking in the short term. It is free from harmful contaminants and acceptable for hydration. However, it is not optimal for long-term use due to the lack of beneficial minerals.
If you’re relying on 25 TDS water daily, consider:
- Remineralizing your water
- Balancing it with mineral-rich foods
- Testing water quality regularly
Aim for a TDS level between 50–150 ppm for the best combination of safety, taste, and nutritional support.
Frequently Asked Questions (FAQs)
Q1: Can 25 TDS water cause health problems?
Not immediately. But long-term use may contribute to mineral deficiency, especially if dietary intake is poor.
Q2: Why is RO water TDS so low?
RO membranes remove up to 99% of dissolved solids, including minerals, leading to ultra-low TDS water.
Q3: How can I test my water’s TDS at home?
Use a digital TDS meter, easily available online. It gives quick results in ppm (mg/L).
Q4: Can low TDS water leach metals from pipes?
Yes, particularly if the plumbing system is old or made of materials like copper or lead.
Q5: Should I stop using my RO system?
Not necessarily. Just add a remineralization stage or adjust the settings to allow partial blending of filtered and unfiltered water.
Conclusion
Understanding TDS is crucial for making informed decisions about your drinking water. While 25 TDS water is technically safe, it may not provide the mineral support your body needs for long-term wellness. By aiming for a TDS range of 50–150 ppm, you strike the perfect balance between purity and health. Whether you’re using RO, bottled, or natural spring water, ensure that your water not only hydrates but also nourishes.