It is true! This quartz watch contains the original basic form of a battery, a galvanic cell. As soon as the battery container is filled with water through slits on the side of the watch, the device starts working.
The galvanic cell consists of two electrodes made of different metals, often copper and zinc. When the electrodes are moistened, an electrochemical process is initiated, and electric current starts flowing – enough to power a quartz watch. The watch must be refilled with water every few weeks to keep this process going.
An important detail for desert regions like Texas, where this watch was invented, is that in case of sustained drought, the watch can be powered with any random liquid, supposedly even beer. Cheers!
Water Watch, Ventu Research, El Paso (Texas), 1977, Inv. 2024-017