Previous parameterization attempts, such as the TIP and OPC models, used density curves only, i. e. density ρ(T ) estimated at single pressure and different temperatures. Thus, it is likely the errors in the temperature derivative properties are already minimized in existing common water models, as we will indeed show. However, we hypothesize that the pressure derivative properties will likely have significant room for improvement as the molar volume (density) surface, PρT (density experimentally measured at different P and T), covers both temperature and pressure derivatives.