Warm water abundances in various low-mass protostars. Class 0 protostars are shown at the top with the values adopted from Persson et al. (2016). The values for Class I objects are derived in this work. Finally, the cold water vapor abundance of TW Hya is indicated as a reference (Hogerheijde et al. 2011; Salinas et al. 2016). The red hashed regions denotes the disk average water abundance. The solid shaded regions (grey for Class 0 and brown for Class I) indicate the water abundance for the inner warm disk after correcting for the 100 K mass. The canonical value of water abundance at 10⁻⁴ is shown with the vertical line if most oxygen is locked up in water.