The experimental ABFE of the trapped water for the BPTI system at 298 K is -4.7 ± 1.0 kcal mol -1 . To the best of our knowledge, this is the only reported experimental value of ABFE of the trapped water across the 13 systems studied here. Using our protocol, we calculated an ABFE of -3.59 ± 0.8kcal mol -1 for the trapped water in BPTI, which is somewhat different from the experimental value, but not outside statistical error. We did not find an explanation for this difference. The study by Barillari et al. reported an ABFE of the trapped water of -4.1 ± 0.5 kcal mol -1 for the BPTI system. However, Ge et al. highlighted that the study of Barillari et al. did not take into account the correct standard concentration of water in their calculations and also included an unnecessary symmetry correction term for water in their free energy estimate. After correcting for the standard concentration and symmetry correction in their calculations, their ABFE for the BPTI becomes -2.1 ± 0.5 kcal mol -1 . The lack of experimental measures of the ABFEs of trapped waters for the other 12 systems studied here made it a challenge to experimentally verify our results. Under these circumstances, we are satisfied to have a well converged estimate that lies within statistical error of the only experimental result.