DALI disc structure for HD 163296. Top panels: gas and dust density structure, the gas temperature, and the H₂O abundance structure. The three main H₂O reservoirs are indicated by the labels s₁, s₂, and s₃. Bottom panels: model predictions of the SED (left), CO ladder (middle), and H₂O fluxes (right). The observed fluxes and 3σ upper µmits are shown as (grey) circles and open triangles, respectively. The representative model shown as a red line and red squares) reproduces the SED (left) and the CO rotational ladder (middle) well but is not able to reproduce the H₂O line fluxes and upper µmits. We note that the H₂O abundances shown here are those of the representative disc model based on the full gas-grain chemistry calculation.