H₂O 2047, a novel by Erwan Barillot, begins with a vivid image of water as a "blue wave, immense, will curl into the metal channels," introducing a story centered on water scarcity and its broader consequences. The narrative follows Léa, a Swiss engineer specializing in water treatment, who relocates from Dubai to a future Switzerland facing a severe water crisis. The novel was inspired by a project with armasuisse, a Swiss defense and security organization, and this background influences the story's detailed and realistic approach. Barillot integrates various technical elements, such as ShAIdes, Blue Corps, Water Defense Force, grey water recycling, and nanostructured membranes, creating a structured system rather than a purely speculative world. The inclusion of technical documents and illustrations by Antoine Petiteaux gives the book the look of a manual that has been lost since 2047. This approach effectively makes the future feel credible by focusing on everyday usage, procedures, and small actions rather than dramatic disasters. However, the novel occasionally falters under the weight of its technical details and explanations, which can slow the pace. Some dialogues seem more like tests of ideas than explorations of character. Fortunately, the narrative becomes more fluid when it shifts away from its prospective commentary, allowing Léa to reemerge as a mother, a daughter, and a woman shaped by past experiences. "After the fury of fire, the liquid stillness. A shock of elements." In these moments, the language becomes more physically simple and almost tangible. Barillot skillfully manages the narrative's progression, using short, dated chapters to quickly shift focus and highlight the significance of water, even in today's world where it flows from taps without incident. The novel reaches its emotional peak with a line from Luca: "You almost died for... water!" This line encapsulates the essence of the story. H₂O 2047 does not aim for an apocalyptic scenario but instead explores the grey area between adaptation, solidarity, control, and the militarization of water. While the novel occasionally lacks ambiguity and some characters struggle under the weight of its speculative framework, it succeeds in transforming a technical problem into a compelling narrative tension. It turns water management into a simple yet deeply political question: who will still be able to drink?