Daily water intake for a adult man?

Silly: There is a common, silly, urban legend about "hydration". The amount of fluid required depends on the individual, the temperature and humidity, the activity, the diet. Consuming very large volumes of water to produce large volumes of dilute urine is a good strategy to manage urinary stones and urinary infections. But is is otherwise silly unless the person enjoys frequent, copious urination.

Simple: No water is necessary.Fluid value in foods or other liquids can easily meet the daily hydration need.As long as they take in enough hydrating materials to pee every 6-8 hours and maintain normal activities they have done enough.