The Zr-2.5 wt%Nb alloy was studied in order to elucidate phase transformations and the distribution/redistribution of hydrogen. The study focuses on understanding the stability of the Zr-H system; surface hydride formation and its transformation during subsequent ageing was inspected in detail, using SEM imaging, EBSD, X-ray diffraction and AFM. During the hydriding process, the H in solution -> gamma -> delta transformation occurred, which resulted in the formation of delta-hydrides on the sample surface. As hydride precipitation occurs, the system enters a metastable state before it reaches a new equilibrium state. The Zr-H system approach to the new equilibrium state was monitored during room temperature ageing over the course of several weeks. The total surface hydride fraction decreased with ageing time. Along with a delta -> gamma phase transformation, partial hydrogen dissolution occurred followed by diffusion out of the surface X-ray diffracting volume into the depth of the sample.