How much water to drink per day (and the answer is not two litres)

Staying hydrated and drinking adequate water is really important for our health. Our body contains about 60% water and we need to have good hydration to maintain, among other things, a correct basal temperature, eliminate waste or transport nutrients. The problem is knowing how much water to drink. We have all heard the famous indication to drink two liters of water a day and some people follow it to the letter by measuring consumption with a bottle of water. The reality is not so simple.

We are going to look at the recommendations of the Institute of Medicine (IOM). We could say that the recommendation they make is that men, in general, consume approximately three liters of water and women about two liters. However, that approximate and general recommendation is that, general. Each one of us has particular conditions, and we must think about them when calculating our ideal water consumption.

This is why you have to take into account variables such as age, sex, level of physical activity, or other things, such as being pregnant or breastfeeding. Therefore, we are going to see more specific recommendations based on different variables.


In the children there is enough variability in the consumption of necessary water based on the age of these. In general, the IOM recommendation is that children between the ages of 4 and 8 should consume about 1 litre of water. For children between the ages of 9 and 13 this consumption increases slightly, and the water consumed should be between 1.65 and 1.89 litres.

In the case of teenagers, between 14 and 18 years the consumption is the highest, should be between 1.89 and 2.60 liters.


The general recommendation for adults over 19 years of age is to consume 3.7 liters for men and 2.7 liters for women. This does not mean that we have to have a bottle of water with the exact measure, and we have to finish it. We can consume water through other drinks or other foods that contain water such as vegetables or fruit.

Of that total for each sex, 3 liters in men and 2 liters in women should be consumed in liquid form, through drinks.

Pregnant and breastfeeding mothers

Pregnant women, on the other hand, should consume approximately 2.36 liters of water.

For breastfeeding women, water consumption should increase to about 3 liters.

Other variables

Age or sex aren’t the only considerations we should have. In addition to that there are other elements that can affect and influence the consumption of water that we must maintain.

  • Level of physical activity: if you do physical exercise, you should consume approximately half a liter more per day. Maybe even more, depending on how long and how hard you train.
  • Ambient temperature: the temperature of the place where we live also influences the amount of water we should consume. If we live in places with high temperatures, we must increase our water intake. In addition, the higher the altitude of our place of residence, the greater should be the consumption of water.
  • Health: if we have health problems such as vomiting, diarrhea or fever, water consumption should also be higher.

In general, according to the Mayo Clinic, we can know that we are consuming the right amount of water if we do not normally feel thirsty and if our urine is practically transparent or very light yellow in color.

Of course, we must be clear that the consumption of water is not done solely through water. It is not necessary to have a 3 liter bottle next to you and drink it whole. There are fruits and drinks and other drinks, such as melon, watermelon or milk, which have high amounts of water and their consumption helps us to achieve the necessary hydration. As well as other fruits and vegetables.

As for excessive water consumption, we have all heard that it can be dangerous. This is called Hypothermia and, although it is difficult to happen, it must be taken into account, especially athletes and children. Therefore, in the case of athletes, if they need a high consumption of water, because of the demand of their sport – very long marathons, etc. – ideally they should also consume drinks that restore their electrolytes.

In any case, it is very rare that this happens, and much less common than dehydration.