a) Composite model for the H₂O emission in NGC 1068 favored in this work. Blue/red indicate ortho/para lines, and the submm H₂O 1−6 lines (Table 1) are indicated. Open squares and triangles show the contribution by a moderate-excitation (ME) and a low-excitation (LE) component, and filled symbols indicate the total emission (see text for details); in both cases the submm H₂O lines 2−6 are pumped through far-IR photons emitted by dust. b) Comparison between the observed fluxes of the H₂O submm lines (black squares, from Spinoglio et al. 2012) and those predicted with the composite model.