Maintaining water balance is linked with optimal physical and cognitive performance, therefore it should be a goal towards individual as well as public health and well being¹.

Water balance is achieved when water intake (including water from all food and drink sources as well as metabolic water production) matches water loss².

Thus, dietary and lifestyle choices must be in agreement with needs, which in turn fluctuate according to a variety of physiological and environmental factors. Relying on thirst is not a safe mechanism for ensuring water balance because the body is already (mildly) dehydrated when signals for thirst occur3.

It follows that one should take conscious and informed actions to develop a satisfactory hydration scheme for each day: understand approximate water needs, observe the level of water loss, recognise all water sources and choose accordingly.

See more here:
http://www.europeanhydrationinstitute.org/wp-content/uploads/2018/05/20130424-Hydration-Diet-Selected-Article-Maria-K.pdf