METHODOLOGY
How h2oMatch Works
Transparent data, honest limitations, and a clear line between information and advice.
h2oMatch is built on one simple principle: the numbers you see should match the numbers on the bottle. This page explains exactly how we collect, verify, and present mineral water data - and just as importantly, what we don't claim to do.
Where the data comes from
Every mineral value shown on h2oMatch - sodium, calcium, magnesium, bicarbonate, fixed residue - comes directly from official product labels published by the bottlers themselves.
We do not estimate values. We do not interpolate from similar waters. We do not source numbers from third-party reviews, blogs, or aggregator websites. If a brand does not publish a parameter on its label, that field is left blank rather than filled in with a guess.
This means the values you compare on h2oMatch are intended to reflect official producer data or reviewed bottle labels, rather than estimates or third-party guesses.
The parameters we track
For each mineral water in the database, h2oMatch tracks:
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Sodium (Na⁺) - one of the most relevant parameters for users who monitor sodium intake
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Calcium (Ca²⁺) - one of the main minerals contributing to total mineralization
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Magnesium (Mg²⁺) - frequently highlighted on labels and relevant for mineral profile
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Bicarbonate (HCO₃⁻) - affects taste, perceived softness, and overall character
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Fixed residue at 180°C, or total mineralization for German-market records. These are different measurements, not interchangeable values.
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Carbonation type - still, lightly sparkling, sparkling, or naturally sparkling
These are the parameters that appear consistently on European and US mineral water labels and that meaningfully differentiate one water from another.
What we deliberately leave out
To stay transparent, here is what h2oMatch does not currently track and why:
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Trace minerals (potassium, sulfates, chlorides, fluorides, silica) - included on some labels but inconsistently. Comparing waters on parameters that half of them don't publish would create misleading rankings.
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Nitrates - a regulated parameter, but not consistently published across all bottlers and countries we cover. Including it would create gaps that are misleading rather than informative.
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Microbiological data - not published on consumer labels. Regulated by national authorities, not by h2oMatch.
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pH - useful in some contexts, but not consistently central to everyday mineral water comparison.
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Bottling date and source location coordinates - relevant to enthusiasts but outside the scope of mineral comparison.
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Packaging type, bottle material, environmental footprint - important topics, but not what h2oMatch is designed to answer.
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Health claims, therapeutic effects, dietary recommendations - see the medical advice section below.
We may expand the parameter list in the future if a parameter becomes consistently available across enough brands.
Our collection and update process
Data is collected through a combination of two methods:
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Manufacturer websites - the primary source whenever the bottler publishes the label values online. This is the most authoritative source and is used wherever available.
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Physical bottle labels - when a manufacturer does not publish complete data online, values are taken directly from photographs of physical bottles, including bottles purchased in different markets to account for regional label variations.
The database is reviewed at least once a year. This cadence reflects how mineral water analyses are actually conducted - bottlers typically commission new analyses every few years, so an annual review is sufficient to catch real changes without introducing noise from minor batch-to-batch variation.
If you spot a value that looks outdated, want to suggest a brand we don't yet cover, or notice a discrepancy between our data and a current label, please email info@h2omatch.com with the bottle name, country, and ideally a photo of the label. We review every message.
What we cover
The database is being built around mineral waters from nine countries:
For each country, we include popular and widely available brands. The selection is based on retail availability and consumer recognition rather than any commercial relationship with bottlers - h2oMatch has no paid partnerships with any of the brands listed.
h2oMatch covers a selection of commonly available mineral waters in each market, including imported brands. Coverage is not exhaustive. Rankings reflect the waters included in our database and may change as products are added or their data is updated.
What this data can and cannot tell you
Even with careful sourcing, mineral water data has real limitations that we want to be upfront about:
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Batch variation. Mineral content can vary slightly between batches within the regulatory tolerances allowed by each country. The values we publish reflect the official label, which represents the typical composition - not every individual bottle measured to the milligram.
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Geological evolution. Mineral springs change slowly over decades. A label printed today reflects the current source analysis, but the source itself is a living geological system. Significant changes prompt new analyses, which then update labels - and our database the next annual cycle.
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Coverage gaps. Not every brand sold in every country is in the database. Smaller producers, private-label store brands, and very local waters may not be included.
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Comparison context. Numbers tell you about composition, not about which water is "best." That depends on your taste, your habits, your dietary context, and what you personally are looking for. h2oMatch helps you see the data clearly - what you do with it is your call.
Information, not medical advice
h2oMatch provides general information about the mineral composition of bottled water. It is not medical advice, nutritional advice, or therapeutic guidance.
If you have a specific health condition - high blood pressure, kidney disease, heart conditions, pregnancy considerations, dietary restrictions imposed by a clinician, or any other medical situation where mineral intake matters - please consult a qualified healthcare professional before making decisions based on the data shown here.
We have written some Learn articles that touch on health-adjacent topics (sodium and blood pressure, calcium and bone health, water during pregnancy). These articles describe what is generally known about the role of these minerals in the body, with references to the values typically found in mineral waters. They are educational, not prescriptive. They do not replace personal medical advice.
The h2oMatch Score and Water Calculator help you find waters that match your stated preferences. They do not diagnose, treat, or recommend any course of action regarding your health.
About this project
h2oMatch is an independent project - not backed by any mineral water company, retail chain, or industry association. It exists because mineral water labels carry a lot of useful information that is hard to compare in a supermarket aisle, and because choosing a water based on its actual composition should be easier than it currently is.
The project is maintained by a single person who handles data collection, the technical platform, and editorial decisions. There is no commercial relationship with any bottler, and no advertising on the site.
Feedback, corrections, suggestions, and questions are all welcome at info@h2omatch.com.
Get in touch
For data corrections, brand suggestions, partnership inquiries, or general questions, write to info@h2omatch.com.
We aim to respond to every message and review every data correction request as part of our annual update cycle (or sooner, if the issue is significant).