Line luminosity of the H₂O 2₀₂–1₁₁ (988 GHz) line emission (top), the H₂O 2₁₁–2₀₂ (752 GHz) data (middle), and H₂O 3₁₂–3₀₃ (1097 GHz) spectra (bottom) versus the bolometric luminosity of the source. The blue plusses correspond to the low-mass Class 0 protostars, the black triangles the low-mass Class I, the green asterisks the intermediate-mass objects and the red cross symbols the high-mass YSOs. The solid line indicates the linear correlation of the logarithm of the total line luminosity, log(L_H2O), and log(L_bol). The dashed line shows the log-log correlation of the luminosity measured for the broader Gaussian velocity component only (cavity shock emission; L_{broad H2O}) and log(L_bol).