Most mineral water bottles in Europe, and many elsewhere, print a typical analysis: a short table of what one liter carries once it leaves the source. It reads like a lab report because it is one, condensed.
The unit: mg/L
Every figure is milligrams per liter. For water, one milligram per liter is effectively one part per million, so you will see ppm on some US labels for the same thing.
TDS, or dry residue
Total dissolved solids is the headline number. European labels usually give it as dry residue at 180 °C: evaporate a liter and weigh what stays behind. In the library it runs from 21 mg/L (Svalbarði) to 13,197 mg/L (Rogaška Donat Mg).
The ions
- Calcium (Ca): firmness and a chalky edge.
- Magnesium (Mg): a faint bitterness at higher levels.
- Sodium (Na) and chloride (Cl): salt, from barely there to savory.
- Bicarbonate (HCO₃): a smooth, rounded weight.
- Sulfate (SO₄): a dry, slightly bitter finish.
- Silica (SiO₂): a silky texture.
- Potassium, nitrate and fluoride: usually small numbers, listed for completeness.
An example
S.Pellegrino lists about 862 mg/L of dissolved solids, with sulfate as its largest single ion. That is why the library describes it as dry with a slightly bitter finish.
Labels change. Brands re-test their sources and figures drift by batch and bottle size, so we date every analysis we publish.