The dynamics of water as subtly perturbed by both the interaction with biomolecules andthe variation of temperature and pressure has been investigated via neutron scatteringspectroscopy. A measurement of inelastic neutron scattering devoted to the study of the coherentTHz dynamics of water in a water-rich mixture with DNA (hydration level of 1 g DNA/15 gD2O) at room temperature is reported. The DNA hydration water coherent dynamics ischaracterised by the presence of collective modes, whose dispersion relations are similar tothose observed in bulk water. These dispersion relations are well described by theinteraction model developed in the case of bulk water, and the existence of a fast sound isexperimentally demonstrated.The behaviour of the collective water dynamics was complemented bystudying the single-particle dynamics of bulk water along the isothermT = 298 K in the pressure range 0.1–350 MPa by means of incoherent scattering. Thisexperiment is an attempt to simulate the change of the water molecular arrangementdue to the interaction with DNA, by increasing the pressure as the presence ofthe biomolecule produces an increase in the density. An anomaly is found in thebehaviour of the relaxation time derived from the quasi-elastic scattering signal,which can be related to the hypothetical second critical point in water. Thisanomaly and the transition from slow to fast sound take place in the sameQ range, thus suggesting that the two phenomena could be related at some microscopiclevel.