The reliability of selected DIII-D vacuum components has been studied to give indications of how well the vacuum confinement would perform if a liquid wall experiment were operated on a device such as the National Spherical Torus Experiment (NSTX). Data from the DIII-D vessel and vacuum system are generally applicable to the NSTX because their designs are similar. The DIII-D has accumulated operating experience data over 15 years of operations, and DIII-D-specific reliability values are comparable to previous reliability estimates for vacuum components.