TempoLife › Features › Mineral water mineral content › magnesium
Magnesium in water
Magnesium in water is already dissolved and ionised, which is the form the gut absorbs best. This page ranks every water in the database by magnesium per litre, sets each against the EFSA adequate intake of 350 mg for men and 300 mg for women, and explains why the 250 mg supplement ceiling does not apply to it.
This is a reference table, not a diagnosis and not a prescription. If a clinician has put you on a sodium, calcium, potassium or fluid restriction, that number comes from them and overrides anything here. Analyses are revised as sources are re-tested, so the label on the bottle you are holding always outranks this page.
The ranking
| Water | Magnesium mg/l | Share of 350 mg | Share of 300 mg | “Contains magnesium” |
|---|---|---|---|---|
| Donat Mg | 1 000 | 285.7% | 333.3% | yes |
| Apollinaris | 120 | 34.3% | 40% | yes |
| Hepar | 119 | 34% | 39.7% | yes |
| Gerolsteiner Sprudel | 108 | 30.9% | 36% | yes |
| Badoit | 85 | 24.3% | 28.3% | yes |
| Contrex | 74.5 | 21.3% | 24.8% | yes |
| S.Pellegrino | 55.9 | 16% | 18.6% | yes |
| Staatlich Fachingen | 46 | 13.1% | 15.3% | no |
| evian | 26 | 7.4% | 8.7% | no |
| Vittel | 20 | 5.7% | 6.7% | no |
| Ferrarelle | 19 | 5.4% | 6.3% | no |
| Buxton | 19 | 5.4% | 6.3% | no |
| Fiji Water | 15 | 4.3% | 5% | no |
| Vichy Catalan | 9 | 2.6% | 3% | no |
| Highland Spring | 8.5 | 2.4% | 2.8% | no |
| Volvic | 8 | 2.3% | 2.7% | no |
| Acqua Panna | 6.8 | 1.9% | 2.3% | no |
| Perrier | 3.4 | 1% | 1.1% | no |
| Voss | 1 | 0.3% | 0.3% | no |
What the ranking is telling you
The distribution is the story. A few waters are genuinely serious magnesium sources, a handful clear the 50 mg per litre labelling line, and the long tail contributes single-digit percentages of a day. If magnesium is the reason you are choosing a water, it is worth being honest about which end of that list you are shopping in: swapping one 10 mg per litre water for another 15 mg per litre water changes nothing.
The very top of the list is a different category again. Waters carrying several hundred milligrams of magnesium per litre are sold as medicinal waters with an explicit drinking regimen — a measured glass, often on an empty stomach — precisely because magnesium at that concentration, usually alongside a large amount of sulphate, works as an osmotic laxative. That is a therapeutic effect, not a hydration strategy, and it is the reason those bottles carry instructions.
Why water magnesium sits outside the supplement ceiling
Most tolerable upper intake levels cover intake from every source. Magnesium is the standing exception: the 250 mg a day figure applies only to magnesium added in supplements and fortified foods, and EFSA excludes magnesium naturally present in food and water from it. The reasoning is mechanical rather than political. The endpoint that defines the limit is osmotic diarrhoea caused by a bolus of readily soluble magnesium salts hitting the gut at once — which is exactly what a tablet delivers and not what a litre drunk across a day does.
That is also why a water carrying 100 mg per litre is unremarkable while a 400 mg supplement is above the ceiling. If you want the full derivation and the food sources that do the heavy lifting — pumpkin and sunflower seeds, almonds, wholegrain rye and oats, buckwheat, legumes and dark chocolate — the magnesium reference page covers it. Water is a supporting player: useful, well absorbed, rarely decisive.
Analyses: the figures each producer publishes on the label or in its technical sheet — see the basis line on every water page. Reference intakes: EFSA Dietary Reference Values. Label claims: Directive 2009/54/EC, Annex III. Mineral-water constituent limits and the fluoride labelling rule: Directive 2003/40/EC. Tap-water parametric values: Directive (EU) 2020/2184. Checked 2026-09-06.
Frequently asked questions
Which mineral water has the most magnesium?
Of the waters listed here, Donat Mg at about 1 000 mg per litre. Below it the field thins out fast: only a handful of waters carry more than 50 mg per litre, and that 50 mg line is the EU threshold for a "contains magnesium" claim.
How much magnesium do I need a day?
EFSA sets an adequate intake rather than a requirement: 350 mg a day for adult men and 300 mg for adult women, with no increase in pregnancy or breastfeeding. An adequate intake is the observed intake of an apparently healthy population taken as sufficient, which is a weaker kind of figure than a derived requirement — worth knowing when a label implies you are short.
Is magnesium from water as good as from a supplement?
It is absorbed at least as well. Magnesium in water is already in solution as a free ion, which is the form the small intestine takes up; food magnesium arrives bound to other things and has to be released first. The practical difference is dose — most waters deliver tens of milligrams per litre, not hundreds.
Does the 250 mg upper level apply to mineral water?
No. EFSA's tolerable upper level of 250 mg a day for magnesium applies only to magnesium added in supplements and fortified foods, and explicitly excludes magnesium naturally present in food and in water. The adverse effect that sets the limit is osmotic diarrhoea from a soluble bolus, which is a tablet problem rather than a water one.
All waters compared
The full analysis table, grouped by mineral content.
Water hardness explained
Degrees, millimoles and parts per million, converted, plus what hardness does and does not do.
Low-sodium water
The 20 mg per litre label rule, and how much sodium a litre of each water really carries.
Water highest in calcium
Calcium per litre ranked, and how much of a day it covers.
Bicarbonate and alkaline water
What bicarbonate is, which waters carry a lot of it, and what it comes packaged with.
Fluoride in bottled water
The EU limit, the under-sevens labelling rule, and where natural fluoride comes from.
See whether you are actually short
TempoLife totals magnesium from everything you log against the reference intake, so you can stop guessing from a label.