Computed intensities of the rotational transitions of ortho‐ and para‐H₂O, plotted against the excitation energy of the emitting level, expressed relative to the energy of the J= 0 =K ground state of para; the intensity of the 557 GHz line of ortho‐H₂O, observed by Codella et al. (2010), is also plotted. See the text, Section 3.5. The error bar associated with the observed line intensity is not visible on the scale of this figure.