Correlation plots showing the integrated H₂O 1₁₀–1₀₁ 557 GHz line intensity scaled to a distance of 200 pc as a function of various envelope parameters; the H₂O intensity is not scaled when comparing to CO 3–2 emission. Class 0 sources are marked in red, Class I sources in blue; sources with bullet emission are marked with crosses, inverse P-Cygni profiles with squares and regular P-Cygni profiles with triangles; the upper limit for TMC1A is marked with an arrow. Strong correlations (|r| > 0.7) are marked with full lines, tentative correlations (0.6 < |r| < 0.7) with dashed lines. The parameters are (from left to right, top to bottom): CO 3–2 emission, L_bol, T_bol, M_env, the evolutionary parameter , F_CO, n(1000 AU) and Δν_max.