Alkaline Water: What's True and Which Mineral Water Works
Basentracker Team
A water’s pH tells you nothing about whether it has an alkalizing effect in your body. Ionized “alkaline water” with a pH of 9 or 10 but few minerals has practically no effect, because stomach acid neutralizes the pH right away. What does have an alkalizing effect is mineral water with lots of bicarbonate (hydrogen carbonate), plus magnesium and calcium. By calculation, one liter with 1,800 mg of bicarbonate provides about as much base as 250 g of spinach. At the store, check the label: from 600 mg per liter, a water may be labeled “contains bicarbonate.”
pH and alkalizing effect are two different things
The pH describes how acidic or alkaline a liquid is in the glass. For your acid-base balance, something else counts: which substances leave acid or base behind in your body after you take them in. It’s the same logic as the PRAL of foods, where the sour lemon turns out to be alkaline.
Pure water with a high pH contains almost no base that could make a difference. One liter of water at pH 9.5 contains only a tiny fraction of a millimole of base. For comparison, a serving of chicken breast brings about 15 to 20 millimoles of acid. Whatever is alkaline in the glass is neutralized right away in the stomach at pH 1 to 2.
ℹ️ What about the carbonation?
Carbonation makes sparkling water slightly acidic in the glass. In your body, it turns into carbon dioxide, which you breathe out. It has no effect on the acid load your kidneys handle. Sparkling and still mineral water work the same.
What matters: bicarbonate and minerals
Bicarbonate (HCO₃⁻, also called hydrogen carbonate) is exactly the substance your body itself uses to buffer acid. Mineral water high in bicarbonate delivers this buffer directly. Magnesium and calcium add to the alkalizing effect, while sulfate and chloride tend to work in the opposite direction.
Studies with bicarbonate-rich mineral waters (usually above 1,500 mg per liter) show a higher urine pH and lower acid excretion by the kidneys, which is exactly the effect of an alkaline diet. Waters low in bicarbonate don’t show this effect, no matter how high their pH.
By calculation, 61 mg of bicarbonate equals one millimole of base. That lets you compare waters with foods:
| Drink or food | Bicarbonate | Base (calculated) | Comparison |
|---|---|---|---|
| 1 L tap water, typical | 100 to 300 mg | about −2 to −5 | nearly neutral |
| 1 L still water, low in minerals | under 100 mg | under −2 | nearly neutral |
| 1 L “alkaline” water, ionized | usually under 100 mg | under −2 | nearly neutral |
| 1 L mineral water, “contains bicarbonate” | from 600 mg | from about −10 | like 150 g of potatoes |
| 1 L mineral water with 1,800 mg | 1,800 mg | about −30 | like 250 g of spinach |
Base from bicarbonate estimated roughly (mmol = mg ÷ 61), not counting the contribution of magnesium and calcium. Comparison values from the Basentracker database: boiled potato −6.5, spinach −12.2 per 100 g.
How to find alkaline mineral water at the store
- Read the label. Every bottle lists its analysis, including bicarbonate (HCO₃⁻) in mg per liter. Above 1,000 mg is clearly alkaline, above 1,500 mg strongly alkaline.
- “Contains bicarbonate” may appear on the label if the water has more than 600 mg per liter.
- Factor in magnesium and calcium. Waters with more than 50 mg of magnesium per liter add an extra alkalizing contribution.
- Check the sodium. Many bicarbonate-rich waters are also high in sodium. If you need to watch your blood pressure or sodium, choose one with less than 200 mg of sodium per liter.
- Compare the price. Expensive water filters and ionizers that only raise the pH bring no measurable benefit for your acid-base balance.
⚠️ Don't overdo it
Bicarbonate-rich water is not a medicine. If you have kidney disease or heart failure, or you are on a low-sodium diet, check with your doctor first whether it makes sense for you and how much. For healthy people, one liter a day is a good addition, but it doesn’t replace vegetables.
Read more: Alkaline drinks at a glance, Drinks in the alkaline food list, The PRAL value explained, Understanding urine pH, Acid-base balance made simple.
Bottom line
“Alkaline water” in the sense of “high pH” is a marketing promise with no effect on your acid-base balance. What has an alkalizing effect is mineral water rich in bicarbonate, magnesium and calcium. By calculation, one liter of it provides as much base as a large serving of vegetables. It’s an easy addition to an alkaline diet, as long as you keep an eye on the sodium.
Drinks count too.
In the Basentracker app, drinks show up in your daily balance with their PRAL per 100 ml, from coffee to juice.
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