H₂O line fluxes as a function of the energy of the upper levels obtained from our MOLPOP-CEP runs. Here we report output predictions for different values of water vapor column density (from left to rightN_H2O = 10¹⁷, 10¹⁸, 10^18.5 cm⁻²) and continuum optical depth (from top to bottomτ₁₀₀ = 0.1, 1.0, 10) as reported at the upper right corner of each panel. The H₂O fluxes in each panel are color-coded according to the dust temperature (T_dust).