Top: continuum-subtracted HIFI spectra of the H₂O 1₁₀–1₀₁ ground-state transition at 557 GHz (E_up = 60 K). The profiles have been decomposed into Gaussian components and the best-fit profile is shown in blue. The offset component is highlighted in magenta for clarity. The baseline is shown in green and the source velocity with a red dashed line. Bottom: same as the top figure, except that the line shown is the excited H₂O 2₀₂–1₁₁ line at 988 GHz (E_up = 100 K). More details on the decomposition are found in Kristensen et al. (2010, 2012) for the NGC1333 sources and Ser SMM3.