In order to test the effect of 'water' at high pressure on the rate of dislocation climb in quartz, we have performed annealing experiments on portions of a quartzite sample previously deformed at 700 ¿C, 10-5 sec-1, and 1500 MPa which had a high dislocation density but few subgrain boundaries. Portions of the deformed sample were annealed at 1500 MPa and 800 ¿C for 1 and 4 days; samples with 0.17 wt % water added have a lower average dislocation density and a greater number of subgrain boundaries than those without water added. Annealing at 800 ¿C for 4 days at 1500 MPa after vacuum drying at 800 ¿C, or at 550 MPa with 0.17 wt % water added, produces no significant change in the dislocation microstructure. These results indicate that: (1) the presence of water-related defect in quartz accomplishes hydrolytic weakening by making the climb of dislocations easier, thus increasing the rate of recovery at a given imposed strain rate, and (2) for laboratory times this weakening requires a pressure >550 MPa. ¿ American Geophysical Union 1989