How much water should you drink per day?

According to Mayo Clinic, about 13 cups of water daily is enough for men, and women need nine cups (one cup equals 8 ounces). However, the clinic adds that how much fluid a person should drink per day depends on factors such as the person's activity level, health and location.

WebMD gives a different guideline: to drink six to eight 8-ounce glasses of water a day. It does explain that some people could need more or less — particularly if they have high activity levels in a hot climate or are pregnant or sick. If someone is drinking enough water, his urine will be clear or light yellow as opposed to darker yellow.