Modulating wetting states of water droplets on a solid surface has great potential in numerous applications such as self-cleaning, heat transfer, and water purification. Present strategies to achieve controlled wettability usually employ surface roughness and/or chemical coating at the nanometer-to-micrometer scale. Here we propose that atomic-scale decoration and patterning with silicones can be used to fabricate superhydrophobic surfaces. Atomic decoration, differing from chemical coatings in the characteristic size and partial coverage, controls wetting states with the atomic precision (several angstroms) at low cost and maintains a long lifetime. We attribute the mechanism of atomic decoration to the decrease in effective potential-well depth, inducing weak interactions between the substrate and water droplet. Our work pushes water wetting to the limit of atomic scales, hinting for a paradigm shift from macroscopic to atomically-precise engineering of wetting states and providing new insights for fabricating superhydrophobic surfaces.