Water gas phase abundance in the TW Hya disk model (from top left to bottom right): standard model (model 1), with 1/1000 of the low ISM metallicity (model 3), C/O ratio of 1.86 (model 4), T_gas = T_dust (model 5), without water self shielding (model 6), water on surfaces (model 7), without water adsorption (model 9), with 100 times higher surface reaction rates (model 10), with two different desorption channels (model 11), with 10 active grain surface layers instead of 2 (model 12), without water photodesorption (the outer water reservoir is gone, model 13), and the standard model with a 100 times higher gas mass in the disk inside 4 AU (model 14). White dashed contours: gas temperatures of 200 and 2000 K. Red dashed contours: vertical A_V. Black dashed contours: minimum of radial and vertical A_V.