Thirst

The player has a Hydration (Thirst) metric which starts at 100% and decreases as time passes in the game. It's displayed in the bottom right corner, under the Hunger metric, and is represented by a blue mug. When the Hydration metric reaches 0% then the Health metric will start to fall. The player will slowly heal again if Hydration is restored to above 0%.

It takes 1L of Water to replenish the Hydration level to 100%, which is 2/3 of a Water Bottle.

1L of water is ~55.6 mol of H2O.

The rate at which the Hydration metric drains from 100% to 0% depends on body (lung?) temperature and difficulty level (this is all based on a hunger/thirst rate in settings of 1.0):

Body Temperature	Easy	Normal	Stationeer
0C	69.4 min	34.7 min	19.8 min
10C	34.7 min	23.1 min	15.4 min
20C	23.1 min	17.4 min	12.6 min
30C	17.4 min	13.9 min	10.7 min

Since 100% Hydration is 55.6 mol, this can also be expressed as H2O mol per minute:

Body Temperature	Easy	Normal	Stationeer
0C	0.8 mol/min	1.6 mol/min	2.8 mol/min
10C	1.6 mol/min	2.4 mol/min	3.6 mol/min
20C	2.4 mol/min	3.2 mol/min	4.4 mol/min
30C	3.2 mol/min	4.0 mol/min	5.2 mol/min

In theory you will consume less Hydration if you can lower your body (lung?) temperature to less than 0C, but your suit won't allow you to do this. On easy difficulty, if you were to reduce your temperature to near -10C, you would nearly stop water consumption, but your lungs will start to take damage at -10C.