Yes, there is a limit to how much water you should drink each day. The specific amount can vary depending on a person’s body weight, physical activity level, the climate they live in, their health status, and whether they’re pregnant or breastfeeding.
As a general guideline, the U.S. National Academies of Sciences, Engineering, and Medicine suggests a daily water intake of about 3.7 liters (or about 13 cups) for men and 2.7 liters (or about 9 cups) for women. This includes total water intake from all beverages and foods.
However, it’s also possible to drink too much water, a condition known as water intoxication or hyponatremia. This typically occurs when someone drinks so much water that their kidneys can’t excrete the excess water. The excess water can dilute the electrolytes in your blood, particularly sodium. When sodium levels fall too low, water enters the body’s cells to balance out the concentrations, which can cause the cells to swell. Swelling in the brain can be particularly dangerous and potentially life-threatening.
That said, hyponatremia is quite rare and generally happens only in extreme situations, such as water drinking contests or in endurance athletes who consume large amounts of water over a short period of time.
If you’re thirsty, it’s a good idea to drink, and if you’re engaging in vigorous physical activity, particularly in hot weather, it’s important to drink enough to compensate for the fluids you lose through sweating. But under normal circumstances, drinking when you’re thirsty and maintaining a diet with sources of electrolytes should be sufficient for staying hydrated and healthy. As always, if you have specific health concerns or conditions, it’s a good idea to consult with a healthcare professional.