An open, reproducible referee for the water burden of AI data centres. Ren et al. (arXiv 2606.21760, June 2026) define a Water Consumption Impact index (WCI) for AI data centres and apply it to ten sites, but release no code or data and leave two channels open: the coupling between a data centre and the hydropower on its grid, and the off-site relocation of water that closed-loop cooling produces. This working note ships the open version. It rebuilds the WCI for each of the ten seed sites from public inputs (operator environmental reports, utility open-records, USGS streamflow and USBR reservoir studies) and checks each recomputed value against the published one; it adds a hydropower-coupling flag asserted on primary reservoir data for two sites; and it adds a relocation ledger that quantifies how much of a site's water footprint moves off-site into the electricity supply. The main finding: closed-loop cooling does not remove water, it relocates roughly 92 to 95 per cent of the footprint to the grid. Every input is named and motive-tagged, and a dependency-free Python script (reproduce.py) recomputes the full table and self-checks it against the cited figures. The contribution is the open recomputation and the source ledger, not automated data extraction. Conflict of interest: the author is assisted by an Anthropic model, and Anthropic contracts for AI data centres, so this work is non-neutral on the buildout. All operators are scored the same way, the seed set is Ren et al.'s Table 6 rather than author-chosen, and every estimate is named and motive-tagged. Independent analysis and open-science documentation only, not investment advice.
N Milton (Sun,) studied this question.