What is TDS in water?
Total Dissolved Solids (TDS) is a measurement of the total concentration of all inorganic and organic substances dissolved in a given volume of water. This includes a variety of elements like minerals (calcium, magnesium, potassium), salts (sodium, chlorides), metals (lead, copper), and organic matter. When water moves through soil, rocks, and pipes, it naturally picks up these dissolved particles. TDS is typically measured in parts per million (ppm) or milligrams per liter (mg/L).
The TDS level is a key indicator of overall water quality, but it's important to understand that the number alone doesn't tell the whole story. A TDS meter measures electrical conductivity to provide a quick estimate of the dissolved ions, but it cannot identify the specific types of solids present. A high reading could mean a healthy level of beneficial minerals or a dangerous concentration of harmful contaminants. Therefore, understanding the composition of your water is more important than just the total amount.
Understanding the ideal TDS range for human health
While there is no single universally mandated "best" TDS level, health organizations and water experts have established general guidelines based on taste, health benefits, and safety. The consensus ideal range for healthy drinking water is not zero but a moderate level that balances purity with essential mineral content.
The ideal range (50-300 ppm)
Many experts and water suppliers consider a TDS range of 50–300 ppm to be excellent or ideal for drinking. Water in this bracket contains a healthy level of beneficial minerals, such as calcium and magnesium, which contribute to good taste and overall health. This range ensures the water is both palatable and nutritionally beneficial for most people. Some sources, like Bisleri, explicitly maintain their water at a TDS of around 150 ppm to provide these benefits.
Acceptable and cautionary ranges
- Acceptable (300-500 ppm): Water in this range is still considered safe to drink, though its taste may be noticeably different due to higher mineral content. It may have a slightly mineralized or distinct flavour.
- Cautionary (500-1,000 ppm): At this level, water can have an unpleasant, metallic, salty, or bitter taste, leading to reduced palatability. While not immediately dangerous, it signals a need for further investigation to rule out harmful contaminants. Many regulatory bodies, like the U.S. Environmental Protection Agency (EPA), set a maximum recommended limit of 500 mg/L.
- Unsafe (Above 1,000 ppm): Consuming water with a TDS level consistently above 1,000 ppm is considered unsafe for regular human consumption. This level strongly suggests the presence of potentially harmful substances and warrants advanced filtration.
The risks of imbalanced TDS levels
Drinking water with either excessively low or excessively high TDS levels can have various effects on your health and your home's plumbing.
Effects of low TDS water (less than 50 ppm)
Water with a very low TDS level, such as that produced by some reverse osmosis (RO) systems without a remineralization stage, is often considered overly pure.
- Mineral Deficiency: Demineralized water lacks beneficial minerals like calcium, magnesium, and potassium, which are important for bone health, muscle function, and heart rhythm. Long-term consumption could lead to deficiencies, especially if dietary intake is insufficient.
- Electrolyte Imbalance: Excessively pure water can disrupt the body's electrolyte balance over time, affecting nerve signals and energy levels.
- Flat Taste: With few dissolved minerals to provide flavour, the water often tastes bland, flat, or insipid. This can discourage people from drinking enough water, leading to dehydration.
- Corrosive Properties: Water with very low TDS is more aggressive and can leach metals, such as lead and copper, from plumbing fixtures, posing a secondary contamination risk.
Effects of high TDS water (above 500 ppm)
High TDS water can result from natural mineral-rich sources, agricultural runoff, or industrial waste.
- Unpleasant Taste and Odor: Water with high TDS often tastes salty, bitter, or metallic, making it less palatable for drinking and cooking.
- Potential Contaminants: A high TDS reading can be a red flag for the presence of harmful contaminants like nitrates, arsenic, lead, or pesticides. Regular testing for specific contaminants is crucial.
- Scaling and Appliance Damage: High levels of minerals like calcium and magnesium contribute to hard water, causing scale buildup in pipes, water heaters, and household appliances. This reduces efficiency and shortens their lifespan.
- Health Concerns: While a high TDS reading on its own isn't a health risk, consuming water with consistently high levels of certain substances like nitrates or lead over time can have serious health consequences, including kidney damage and hypertension.
How to check and adjust your water's TDS
Determining and managing your water's TDS is a straightforward process.
How to check TDS levels
The most common method for a quick check is using a digital TDS meter.
- Get a TDS meter: These are affordable and widely available devices.
- Turn it on: Remove the cap and turn on the device.
- Dip the probe: Dip the metal probes into a glass of your drinking water, ensuring they are fully submerged but not touching the container's bottom or sides.
- Wait for the reading: The meter will display the TDS level in ppm (parts per million) within a few seconds.
For a more detailed analysis, a professional water quality lab test is recommended to identify specific contaminants.
How to adjust TDS levels
Depending on your needs, you can either lower or raise the TDS level.
- Reducing high TDS: Reverse Osmosis (RO) systems are the most effective method for removing a wide range of dissolved solids, including most contaminants. Distillation and deionization are also highly effective.
- Increasing low TDS: If you use an RO system, you can use a post-filter remineralization cartridge or a TDS controller to add beneficial minerals back into the water. This restores a healthy mineral balance and improves taste. Alternatively, you can add food-grade mineral drops to your drinking water.
TDS comparison: Low vs. Ideal vs. High
| Feature | Low TDS (e.g., < 50 ppm) | Ideal TDS (e.g., 50–300 ppm) | High TDS (e.g., > 500 ppm) |
|---|---|---|---|
| Taste | Flat, insipid, or bland. | Pleasant, crisp, or neutral. | Bitter, metallic, salty, or distinct. |
| Mineral Content | Lacks essential minerals like calcium and magnesium. | Contains a balanced, healthy level of minerals. | Contains excessive minerals, potentially unbalanced. |
| Health Impact | Can lead to mineral deficiencies and potential electrolyte imbalance long-term. | Provides essential minerals, supporting hydration and health. | May signal harmful contaminants; can lead to appliance scaling and reduced palatability. |
| Purity | Often considered highly pure, but doesn't guarantee microbiological safety. | High purity is balanced with healthy mineral content. | Purity is compromised by excessive dissolved solids; may contain harmful contaminants. |
| Treatment | May require a remineralization filter to add beneficial minerals back in. | Often requires no additional treatment beyond basic filtration. | Requires advanced filtration like Reverse Osmosis (RO). |
Conclusion
The question of which TDS is best for the human body is not about a single number, but about finding a healthy balance. The ideal TDS range of 50–300 ppm provides the best of both worlds: water that is pure from contaminants while containing a beneficial amount of essential minerals. This balance ensures superior taste and promotes better hydration and overall health. Both excessively low and high TDS levels present potential issues, from mineral deficiencies and a flat taste to unpleasant flavours and the risk of harmful contaminants. By regularly testing your water with a TDS meter and using appropriate filtration or remineralization techniques, you can ensure your water is in the optimal range. The key takeaway is to aim for a balanced, mineral-rich water rather than pursuing an unrealistic or potentially unhealthy zero-TDS goal. For more detailed guidelines on drinking water quality, consult resources like the World Health Organization's report on total dissolved solids. WHO guidelines.
