The experimental downshifts from the symmetric water monomer stretch in the test set span a range of 8-203 cm -1 and thus exclude the more challenging strong hydrogen bonds, where the likelihood of anharmonic resonances increases substantially. None of the 10 test systems involves a proven b2lib resonance , where the water bending overtone (b2) and hydrogen bond libration (lib) ternary combination band steals intensity from the O-H stretch fundamental. Therefore, the raw experimental data can be compared directly to the theoretical predictions, keeping in mind that there may be some mode mixing issue for the multichromophore systems MLA, TFA and PCD. Only in the MLA case is this mixing supported by experiment.