Polyethylene glycol (PEG) hydrogel are commonly used as both scaffolds and drug delivery systems to aid in cellular differentiation, thus developing a good understanding of their water properties is key to PEG optimisation. Terahertz (THz) imaging has previously been used to analyse the water content inside polymer films in ambient environment. Here, we apply this approach to extract the desorption profiles of PEG hydrogels of four concentrations producing results that indicate confinement effects due to porosity on the diffusional properties of water. These preliminary data therefore highlight the broad applicability of THz imaging for the analysis of water properties of PEG hydrogels.