The amount of water an individual needs to drink each day can vary depending on factors such as age, sex, body weight, and activity level. However, a general guideline is to drink at least eight 8-ounce glasses of water per day, which is about 2 liters or half a gallon. This is known as the 8x8 rule.
It's important to note that this is a minimum requirement and some people may need to drink more water depending on their activity level, and the climate they live in. For example, if you are physically active or live in a hot climate, you may need to drink more water to stay hydrated. The color of your urine is a good indicator of how hydrated you are, if it's pale yellow, you are well hydrated, if it's dark yellow or amber, you need to drink more water.
Additionally, it's also important to note that water intake can come from other sources such as fruits and vegetables which contain water, and other beverages like herbal teas or caffeine-free drinks. However, it's recommended to avoid sugary drinks or drinks high in caffeine, as they can dehydrate the body.