Top: FWZI of the H₂O 2₀₂–1₁₁ (988 GHz) emission line versus the bolometric luminosity. Middle: same as top panel but for the ¹²CO J = 10–9 and J = 3–2 observations. Bottom: ratio of the ¹²CO and H₂O 2₀₂–1₁₁ FWZI values as a function of L_bol. The blue plus symbols correspond to the low-mass Class 0 protostars, the black triangles the low-mass Class I, the green asterisks the intermediate-mass objects, the pink crosses the high-mass YSOs for which the ¹²CO J = 3–2 spectra are used, and the red cross symbols the high-mass object for which ¹²CO J = 10–9 data are available (see San José-García et al. 2013). The low- and intermediate-mass sources with detected EHV components are surrounded by a box, as well as the high-mass YSO with triangular water line profiles.