What is TDS in water, and does it affect taste?
TDS is one of the most useful figures on any bottle of water, and one of the least explained. It sits at the center of how a water reads on the palate, yet most labels reduce it to a single number with no context. This is what that number means, how it is arrived at, and what it tells you before you pour.
What TDS is
TDS stands for total dissolved solids: the combined content of all minerals dissolved in a water, measured in milligrams per litre (mg/L), sometimes written as ppm (parts per million). The two units are used interchangeably in practice. What makes up that total is a short list of ions, mainly calcium, magnesium, sodium, potassium, bicarbonate, sulfate, chloride, and silica. A water's TDS is the sum of these, and its character comes as much from the proportions among them as from the total itself. Two waters can share a TDS figure and taste nothing alike, because one leans on bicarbonate and the other on sulfate.
How it is measured
There are two methods, and they answer slightly different questions. The reference method is gravimetric: a filtered sample is evaporated to dryness and the remaining residue is weighed, giving a direct figure in mg/L. This is the number a laboratory reports and the one you should trust on a mineral analysis. In the field, TDS is estimated from electrical conductivity using a TDS meter, since dissolved ions carry a current. A conductivity reading is fast and portable, but it is an approximation converted to mg/L, not a true weight. When you see a precise published figure for a bottled water, it comes from the gravimetric method, not a handheld meter.
What low, medium and high TDS taste like
In general terms, TDS tracks with weight on the palate. A very low-TDS water reads light and clean, sometimes almost neutral, with little to get in the way of whatever it accompanies. A medium-TDS water reads balanced and rounded, with enough mineral presence to have a texture of its own. A high-TDS water reads full and firm, and at the upper end can turn savory or saline.
The specific ions matter as much as the total. Bicarbonate softens a water and rounds its edges. Sulfate and chloride can read savory or slightly bitter. Sodium reads saline. This is why two high-mineral waters can feel different in the mouth: the total tells you how much is dissolved, and the composition tells you what kind of impression it leaves.
The range across the waters we carry
Our catalog runs across nearly the entire spectrum, which makes it a useful way to hear the differences. At the light end sit Voss at around 22 mg/L and Icelandic Glacial at around 62 mg/L, both very low, both close to neutral. In the low-to-medium band are Acqua Panna at around 130 mg/L, Tŷ Nant at around 165 mg/L, and Evian at around 357 mg/L, the everyday, rounded middle of the range.
Higher up, the waters gain firmness: Perrier at around 475 mg/L, Borsec at around 900 mg/L, and S.Pellegrino at around 970 mg/L. Higher still, Vichy Catalan reaches around 3,052 mg/L, a genuinely high-mineral, saline water. And at the far edge, Donat Mg sits at around 13,000 mg/L, an outlier magnesium-rich water drunk in small measures for its mineral content rather than at the table. Each of these figures is listed in the Composition panel on the product's own page, alongside its pH, so you can check the exact number for the bottle in front of you.
How to choose a TDS level for a given context
Once you can read the number, choosing becomes straightforward. For delicate food, a raw fish course, a subtle broth, a young white wine, reach for a low-TDS still water so it stays out of the way and does not compete. For an aperitivo, or to cut through rich and fatty food, a higher-mineral or sparkling water gives you the structure and lift you want. For everyday drinking, a medium-TDS water suits most palates, present enough to be interesting, mild enough to drink all day.
The distinction between still and sparkling is only part of the picture, and where a water comes from shapes its mineral load. If you want the fuller background, see our guides to spring water versus mineral water versus purified water and to the best premium sparkling waters compared.
The TDS of every water we carry is listed in the Composition section of its product page at Artisanal Aqua, next to its pH, so you never have to guess. Browse the range, starting with our still waters, and read the number before you choose.