Thirst

You can enable a thirst need in mod settings, this adds a basic thirst need that colonists will need to keep satisfied by eating food and drinking from fountains, sinks, water tubs or surface water. If water is contaminated they will have a high chance of getting sick.

All food types including modded foods have water content, when the food bar is above 50% it will transfer water to the thirst bar, below 50% the thirst bar will start to fall again, so a colonist can stay alive only eating food and not drinking, but they will be in a constant state of mild dehydration which makes them grumpy and sickly but also increases hunger so they eat more food for the water content.

The thirst need will fall at different rates depending on if the colonist is sleeping, doing physical activity like hauling or having sex, if they are sick, or if the weather is hot. So if pawns are busy working in hot mine shafts make sure to supply them with a water tub, fountain, or water butt so they can have a drink.

Doctors can administer fluids to patients that are bedridden.

There are no bottles of water because their carried food contains water. Water butts can be filled and carried with caravans to supply water, as the water is used the water butt reduces in weight and value.