The recommended daily water intake varies depending on factors such as age, gender, activity level, and environment.

• For adult men, the typical recommendation is about 3.7 liters (approximately 13 cups or 125 ounces) of total water per day , including water from all beverages and food.
• For adult women, the recommendation is about 2.7 liters (approximately 9 cups or 91 ounces) per day in total.
• Children and teenagers have varying needs based on their age, ranging from about 5 cups (40 oz) for younger children to 8-11 cups (64-88 oz) for older teens.
• People who are physically active, live in hot or humid climates, or are pregnant or breastfeeding generally require more water.

Rather than adhering strictly to a fixed number of glasses, thirst is often the best guide for individual water needs. Common advice like "drink eight 8-ounce glasses a day" is a general guideline but not scientifically precise for everyone. The water intake includes all fluids consumed, not just plain water. Thus, the typical adult daily water intake is about 2.7 to 3.7 liters (9 to 13 cups), adjusted based on individual circumstances.