Men should drink about 13 glasses of water and other fluids per day, and women should drink about 9 glasses, according to Mayo Clinic. One glass equals 8 ounces, or 1 cup. Exercise, humidity, illness and pregnancy are some situations that cause a person to need to drink more fluids.
Pregnant women should drink about 10 glasses of fluids per day, and breast-feeding women should drink about 13 glasses.
Mayo Clinic points out that people get about 20 percent of their water and fluid needs from food sources. Water is also in other drinks, such as soda and sports drinks. A person who exercises intensely should consume a sports drink that has sodium because the body loses sodium through sweat.