TDS (Total Dissolved Solids) in Drinking Water
Complete water quality profile for total dissolved solids (TDS), including sources, measurement methods, health considerations, taste impacts, treatment technologies, and drinking water guidance.
Quick Facts
What Is TDS?
Total Dissolved Solids (TDS) refers to the combined concentration of dissolved minerals, salts, metals, and other substances present in water.
Unlike turbidity, dissolved solids are generally invisible and cannot be removed through simple sediment filtration.
Why TDS Matters
TDS influences water taste, mineral content, scaling potential, and overall water quality perception.
Main Sources of TDS
Natural Minerals
Groundwater naturally dissolves minerals such as calcium, magnesium, sodium, and potassium from rocks and soils.
Saltwater Intrusion
Coastal aquifers may experience elevated TDS when seawater enters freshwater sources.
Agricultural Activities
Fertilizers and irrigation return flows can increase dissolved solids in water sources.
Industrial Sources
Industrial discharges and wastewater may contribute dissolved substances.
How TDS Affects Drinking Water
Taste
Low TDS water may taste flat, while higher TDS levels can create salty, bitter, metallic, or mineral tastes.
Scaling
High mineral concentrations can contribute to scale formation in pipes, appliances, kettles, and water heaters.
Corrosion
Very low TDS water can sometimes be more corrosive to plumbing materials.
Typical TDS Levels
| TDS Level | General Interpretation |
|---|---|
| 0 – 50 ppm | Very low mineral content |
| 50 – 150 ppm | Low mineral content |
| 150 – 300 ppm | Moderate mineral content |
| 300 – 600 ppm | Higher mineral content |
| 600+ ppm | Very high dissolved solids |
How TDS Is Measured
- Digital TDS meters.
- Electrical conductivity measurements.
- Laboratory analysis.
- Municipal monitoring programs.
- Private well testing.
TDS Reduction Methods
| Method | Effectiveness | Notes |
|---|---|---|
| Reverse Osmosis | Excellent | Most common household TDS reduction technology |
| Distillation | Excellent | Highly effective but energy intensive |
| Deionization | Excellent | Common in specialized applications |
| Water Softening | Partial | Changes mineral composition but does not significantly reduce TDS |
| Sediment Filters | Poor | Do not remove dissolved solids |
Related Water Quality Parameters
Frequently Asked Questions
What does TDS mean?
Total Dissolved Solids, the total amount of dissolved substances in water.
Does high TDS mean contaminated water?
Not necessarily. TDS measures dissolved material quantity, not contaminant toxicity.
Can a TDS meter identify contaminants?
No. It only measures total dissolved content, not specific substances.
Can reverse osmosis reduce TDS?
Yes. Reverse osmosis is one of the most effective TDS reduction methods.
Is low TDS always better?
Not necessarily. Very low TDS water may lack beneficial minerals and may taste flat.
Quick Summary
TDS measures the total concentration of dissolved substances in water. While it does not directly indicate contamination, it strongly influences taste, scaling potential, and water quality perception. Reverse osmosis, distillation, and deionization are among the most effective technologies for reducing TDS levels.