The label reveals more than the advertising: how to tell from the milligrams whether a water suits sport, baby food, high blood pressure or simply a good taste.
In short
- Water with more than 150 mg/l calcium and more than 50 mg/l magnesium may be labelled “contains calcium” and “contains magnesium”.
- Low in sodium means under 20 mg/l, important for high blood pressure and for baby food.
- Bicarbonate above 600 mg/l buffers acid and makes water taste soft.
- Sulphate above 200 mg/l has a mildly laxative effect, chloride tastes salty.
What has to be on the label
In Germany, the Mineral and Table Water Ordinance (Mineral- und Tafelwasserverordnung) requires natural mineral water to carry the analysis of its main constituents: the spring, the place, the date of the analysis and the dissolved minerals in milligrams per litre. Table water and spring water do not have to. So if you are looking for numbers, reach for mineral water.
The four numbers that count
- Sodium: Under 20 mg/l it may be called “low in sodium” and is meant for baby food and low-salt diets. Over 200 mg/l it is a water for sport and heat, where salt is lost.
- Calcium: From 150 mg/l, “contains calcium”. One litre then covers a fifth to a quarter of the daily requirement. Good for everyone who eats few dairy products.
- Magnesium: From 50 mg/l, “contains magnesium”. One litre then supplies roughly 15 per cent of the daily requirement. For sport and muscles, and for people with cramps.
- Bicarbonate: From 600 mg/l the label may say “contains bicarbonate”. It buffers acid, tastes soft and round and makes water easy on the stomach, including with heartburn.
The supporting cast
Sulphate above 200 mg/l stimulates digestion and is laxative in large amounts. Chloride gives a salty note, together with sodium. Potassium is usually low and unimportant. Fluoride above 1 mg/l is not ideal for children, but is permitted below 1.5 mg/l. Silicon (silicic acid) is a trend mineral with no proven benefit.
What the total tells you
The sum of all dissolved substances, often given as “total mineralisation” or dry residue, tells you how “heavy” the water tastes. Below 500 mg/l it is light and neutral, above 1,500 mg/l it is strong, mineral and sometimes salty. For everyday drinking, medium values are the most pleasant; for sport it can be more. What the TDS value means here is explained in the article Understanding TDS.
The label and carbonation
The German labels “Classic”, “Medium” and “Naturell” (sparkling, lightly sparkling, still) describe only the CO2 content: roughly 7 to 8 g/l, 4 to 5 g/l and under 1 g/l. Whether the carbonation comes from the spring or has been added is written in small print. For your health, both are the same. More in the article Is carbonated water bad for you?
Frequently asked questions
Is expensive mineral water better?
Price says nothing about composition. A discounter’s water at 19 cents can contain more magnesium than a designer bottle at four euros.
What does “suitable for the preparation of infant food” mean?
Sodium under 20 mg/l, nitrate under 10 mg/l, fluoride under 0.7 mg/l, sulphate under 240 mg/l, manganese and uranium below the limit values. The water may then be used without boiling, provided the bottle has just been opened.
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