AC magnetic susceptibility at medium frequencies suggests a paramagnetic behavior of pure water

► AC magnetic susceptibility of pure water at different temperatures (37 °C, 25 °C and −1 °C). ► And salty water at different concentrations (0.25 M, 0.1 M and 1 mM) is studied. ► Paramagnetism in pure water at 25 °C and 37 °C is observed between 500 kHz and 1 MHz. ► The AC magnetic susceptibility is negative for ice and salty water regardless the frequency.