Understanding Total Dissolved Solids (TDS)
Total Dissolved Solids (TDS) measure the inorganic salts and small amounts of organic matter dissolved in water. These substances can come from natural sources, sewage, and industrial runoff. A very low TDS level indicates a higher level of purity. Water with an extremely low TDS can taste 'flat' or 'insipid' because the minerals that often provide a pleasant flavor have been removed. The World Health Organization classifies water with excellent palatability as having less than 300 mg/L TDS. Brands with very low TDS, often below 50 mg/L, include those that have undergone significant purification.
The Absolute Lowest: Distilled Water
Distilled water has the lowest mineral content. The distillation process involves boiling water and collecting the resulting steam as it condenses. This method leaves behind all impurities, including minerals, resulting in water with a TDS of essentially 0 ppm. While exceptionally pure, this process is energy-intensive and can result in a bland taste. Distilled water is more commonly used in medical applications, laboratories, and household appliances like irons and humidifiers to prevent mineral buildup. Some bottled water brands, such as Smartwater, even start with a distillation process before adding back a proprietary blend of electrolytes for taste.
Fractional Vapor Compression Distillation
Some manufacturers, like Le Bleu, employ advanced distillation techniques such as Fractional Vapor Compression Distillation. This five-step process is designed to produce water that is 11% hydrogen and 89% oxygen. The company claims their water is so pure it has no expiration date.
A Common Alternative: Reverse Osmosis (RO) Purified Water
Reverse Osmosis is a widely used water purification method that achieves very low mineral content. It forces water through a semi-permeable membrane under pressure, leaving impurities and minerals behind. Several popular bottled water brands utilize this method.
- Aquafina: Aquafina uses a multi-stage purification process that includes reverse osmosis. The company states that its average TDS reading is 4 ppm, well below the FDA's 10 ppm standard for purified water. Its purification system effectively removes most dissolved solids.
- Dasani: Dasani uses reverse osmosis and adds a proprietary blend of minerals back for taste. This results in a slightly higher TDS than Aquafina, but still well within the very low range.
- Boxed Water: This brand uses reverse osmosis filtration and UV/ozone disinfection. It typically has a very low mineral content, often measuring around 2 ppm. Its packaging is designed to be more environmentally friendly.
Comparing Brands: A Look at TDS Levels
This table compares the Total Dissolved Solids (TDS) of several bottled water brands. TDS is key for determining which bottled water has the lowest mineral content.
| Water Type | Brands (Examples) | TDS (Approx. ppm) | Mineral Content | Processing Method |
|---|---|---|---|---|
| Distilled | Le Bleu, Smartwater (Pre-electrolytes) | 0-2 ppm | Extremely Low (Near-Zero) | Distillation |
| RO Purified | Aquafina | ~4 ppm | Very Low | Reverse Osmosis |
| RO Purified (Re-mineralized) | Dasani, Smartwater | ~25-28 ppm | Low | RO + Added Electrolytes |
| Natural Spring (Low TDS) | Voss | ~23-40 ppm | Low | Natural Artesian Source |
| Natural Spring (Higher TDS) | Evian, Fiji | >100 ppm | Medium to High | Natural Artesian Source |
Conclusion: Choosing the Lowest Mineral Content Water
Distilled water is the technical winner, offering a TDS of 0 ppm. However, many people prefer the taste and convenience of reverse osmosis (RO) purified brands. Brands like Aquafina provide a consistently very low mineral count. The choice often comes down to specific needs—absolute purity for appliances versus palatable, clean-tasting water for drinking. For those requiring extremely low TDS, such as for specific medical or laboratory applications, verifying the purification method is key. For a full breakdown of TDS values and their health implications, the World Health Organization offers extensive guidance on drinking water quality.
Further Reading
For more in-depth information about water purification and total dissolved solids, consult the World Health Organization's reference document.
World Health Organization Guidance on TDS
Which bottled water has the lowest mineral content?
The Bottom Line: Distilled water has the lowest mineral content (0 ppm TDS), but Reverse Osmosis (RO) purified waters like Aquafina are a very close and widely available option.
Distillation vs. RO: Distillation uses boiling and condensation, while RO uses a semi-permeable membrane to filter water; both are effective at removing minerals.
Taste Differences: Low-mineral water can have a flat taste, which is why some RO brands add electrolytes back in for flavor.
Practical Applications: Low-mineral water is best for appliances like humidifiers and irons to prevent mineral buildup.
Health Considerations: The minerals removed from water can be obtained from a balanced diet, so low-mineral water is safe for regular consumption.
Brand Purity: Aquafina is an excellent example of a commercially available purified water with a consistently low TDS reading.
