Averaged H₂O 2₁₁–2₀₂/2₀₂–1₁₁ ratio (top panel) and H₂O 3₁₂–3₀₃/2₀₂–1₁₁ line intensity ratio (bottom panel) as a function of offset velocity for the low-mass protostars (LM; grey area from Mottram et al. 2014), intermediate-mass objects (IM; green line and asterisks), and the high-mass YSOs (HM; red line and crosses). The dashed green and red regions indicate the calculated standard deviation of the line ratio for each velocity channel.