Everybody publishes a number. Nobody publishes one you can check.
Five questions asked of the largest data centre operators, each answerable from public documents. Four of them separate the field. The fifth does not separate anyone, because on the fifth nobody scores at all, and that is the whole reason this page exists.
Discloses
Is any water figure published at all?
Around 47 per cent of operators measured their water use in 2025, and seven of the top twenty publish no WUE. This column fails first and fails often.
Basis stated
Is it consumption or withdrawal, and does the operator say which?
AWS publishes 0.12 L/kWh on a withdrawal basis and Microsoft 0.27 L/kWh; the bases differ, so the numbers cannot be compared. An unstated basis makes a good-looking figure meaningless.
Site level
Can a community see the facility next to them, or only a fleet average?
A global average tells a council nothing about the building in their township. More than a dozen shareholders have now formally asked Amazon, Microsoft and Google for site-specific figures.
Measured
Is the figure metered, or calculated by the claimant?
The return side is rarely metered anywhere, so consumption is usually withdrawal minus an assumption.
Checkable
Could a third party verify it without asking the operator?
Nobody assessed so far scores here. That is the opportunity, stated as a column.
Open until 30 September 2026
This is version 0.1 and it is preliminary: assessed from published secondary sources on 31 August 2026, with every row to be re-checked against the operator’s own report before v1.0. If a cell is wrong we would rather be corrected than be right by luck.
The assessment
Read the last column first. Every operator here publishes something, several publish carefully, and not one publishes a record anybody outside the company could verify.
| Operator | 1. Discloses | 2. Basis stated | 3. Site level | 4. Measured | 5. Checkable | Grade |
|---|---|---|---|---|---|---|
| EquinixColocation | yes | yes | no | ? | no | C |
| Digital RealtyColocation | yes | yes | no | ? | no | C |
| GoogleHyperscaler | yes | yes | part | ? | no | C |
| MicrosoftHyperscaler | yes | yes | no | ? | no | D |
| Amazon Web ServicesHyperscaler | yes | part | no | ? | no | D |
| MetaHyperscaler | yes | yes | part | ? | no | D |
| Vantage Data CentersColocation | no | no | no | no | no | F |
| CyrusOneColocation | ? | ? | ? | ? | no | — |
Equinix · C
Reports an annual average WUE of 0.95 for 2024, and unusually publishes two figures: the whole portfolio, and evaporative-cooled sites separately. That separation is more granular than most peers manage. Still a fleet view, and nothing a third party can check.
claims register C-029 · confidence M
Digital Realty · C
Reports WUE 1.58 and 43 per cent non-potable intake across the regional portfolio. Disclosing the source composition is rare and worth crediting. Fleet level, unverifiable.
claims register C-030 · confidence M
Google · C
Publishes absolute consumption, up 34 per cent to 10.9 billion gallons in 2025, and states the basis. Reporting covers owned and leased sites but omits third-party operations, so the scope has a hole in it that the headline number does not show.
claims register C-004, C-026 · confidence M
Microsoft · D
Publishes WUE at 0.27 L/kWh and states that all designs since August 2024 are zero-water closed loop, which is a meaningful design commitment. But water figures are aggregate with no site-level breakdown, so a community cannot see its own facility.
claims register C-003, C-005, C-027 · confidence M
Amazon Web Services · D
Publishes WUE 0.12 L/kWh. The basis is withdrawal, which is not the same quantity Microsoft's 0.27 measures, and the two are routinely compared as though they were. Fleet average only.
claims register C-003 · confidence M
Meta · D
Reports 5,637 megalitres, up 51 per cent between 2020 and 2024. Reporting covers owned sites only, excluding leased and under-construction facilities, which is a scope exclusion rather than a measurement problem, and it is the material fact here.
claims register C-025 · confidence M
Vantage Data Centers · F
Published ESG reporting reviewed to date discloses no water use or water effectiveness figure. This is an absence, not a poor number, and we would rather be corrected than be wrong: right of reply is open.
claims register C-031 · confidence L
CyrusOne · not graded
Operates closed-loop air cooling on its Iberian campuses to remove municipal reliance, which is a design claim rather than a disclosure. No published operator-wide water figure has been established yet, so this row is not graded.
no established claim · confidence L
How this is scored, so you can disagree with it properly
- Every cell traces to a source recorded in our public claims register, with the date it was accessed and a confidence mark. Nothing here was inferred from a company’s reputation.
- UNKNOWN is not a bad grade, it is an honest one. Where we could not establish a fact, the cell says so and the row is not graded on it. CyrusOne is ungraded for exactly this reason.
- An absence is recorded as an absence. Vantage is marked as publishing no water figure in the ESG reporting reviewed, which is a claim about what we found, not about what exists. Confidence is marked low and right of reply is open.
- v0.1 is assessed from published secondary reporting. Before v1.0 every row is re-checked against the operator’s own primary report, and any correction received is applied and credited.
- Grades measure checkability, not virtue. An operator using very little water badly documented scores worse than a heavy user who publishes clearly. That is deliberate: this index is about whether a number can be trusted, not whether it is small.
The fifth column is not a gap in our research. No operator publishes a record a third party can verify, because until recently there was no way to. There is now, and you can run it yourself →
Questions
Which data centre operators disclose their water use?
Most large operators publish something. Google reports absolute consumption, Microsoft and AWS publish WUE, Meta reports volume for owned sites only, and Equinix and Digital Realty both publish portfolio WUE. Around 47 per cent of operators measured water use at all in 2025, and seven of the top twenty publish no WUE figure.
Can you compare data centre WUE figures between operators?
Not reliably. AWS publishes 0.12 litres per kilowatt-hour on a withdrawal basis and Microsoft publishes 0.27, and those measure different quantities. Voluntary reports also use different scopes, and they do not consistently include the indirect water embedded in electricity.
Does any data centre operator publish a water figure that can be independently verified?
Not among the operators assessed here. Every published figure rests on the operator's own calculation, and none is accompanied by a record a third party could check without asking the operator. That is the finding this index exists to make visible.
What is the difference between water withdrawal and water consumption?
Withdrawal is what a facility takes. Consumption is what it takes minus what it returns. Because the return side is rarely metered anywhere, published consumption is usually a withdrawal figure with an assumption subtracted from it.
How is The Water Line scored?
Five criteria: whether any figure is disclosed, whether the basis is stated, whether it is site level or a fleet average, whether it is metered or calculated, and whether a third party could check it. Every cell carries its source. Anything not established is marked UNKNOWN rather than guessed, and version 0.1 is preliminary with right of reply open.