Abundance of gas-phase H₂O in a representative model for the HL Tau disk (colored background). The orange, pink, and cyan contours indicate the τ_dust = 1 surface for the lines in Table 3 in the mid-IR, far-IR, and (sub)millimeter, respectively. In the middle and right panels the solid and dashed lines indicate the long- and short-wavelength ends of the range of lines in Table 3, in the far-IR and (sub)millimeter, respectively. The water snow surface in the model is indicated with the black contour.