Water interfaces differ from the bulk, in both their physical structure and chemical composition. In particular, the role of the termination of the hydrogen-bonded network, the role of charges at interfaces, and the effect of charges on the arrangement of counterions and water have been much debated. These charges also affect the chemical dynamics occurring at water interfaces. For instance, charge is relevant for “on-water chemistry” – chemistry at the open water surface, relevant for both technologies and chemical processes in the atmosphere. My presentation will show how we can characterize the outermost monolayer of water at an interface, quantify the interfacial ion distribution, and follow chemical conversion at water surfaces and interfaces in great detail using surface-specific vibrational spectroscopies.