Water still holds very intricate questions, of which some were tackled in this work. Methods used were FTIR-ATR spectroscopy, isotopic substitution, difference spectra and quantum mechanical calculations. The symmetric and asymmetric stretch vibrations were identified under the OH-stretch band. A new approach was presented to identify the first overtone of the waters’ bending mode. The existence of quasi free OH groups was proven. Two features were identified in the spectra of aqueous solutions to be the result of anionic interaction and the decrease of the H-bonded network. The behaviour of the network peak was correlated to the cationic, while the free OH groups are important for the explanation of the anionic Hofmeister series. It was found that ATR spectroscopy is very convenient for the observation of brine rejection and hydrate formation.