Maybe you've heard that you should drink 8 to 10 glasses of water a day, but this advice is generally dismissed by nutritionists and medical experts. We lose most of our water through urination, and the rest through other body processes like breathing and sweating. All this lost water eventually needs to be replaced, but we actually get about 20 percent of our required water from the food we eat. Many fruits and vegetables are almost entirely water by weight, and even foods like hamburgers and bagels are high in water content. People used to warn against drinking caffeinated drinks as part of your daily intake because of their diuretic effect, so that drinks like tea and coffee weren't counted as part of your daily water intake. However, the water in caffeinated drinks certainly outweighs the dehydrating effects of the caffeine so that there's no net loss of water. If you've tried to drink 8 glasses of water a day, you've probably noticed that you're heading to the bathroom every half hour. Most of the time simply having beverages with your meals and sipping water or other drinks throughout the day is enough. Some factors that affect your need for water are humidity and how much you sweat in the heat and during exercise, so increasing your water intake is important during and after a workout. Paying attention to your body's signals, such as the color of your urine or your sense of thirst, is generally sufficient to help you remain hydrated.