How much water should we be drinking?
You may have heard that you should aim to drink eight 8-ounce glasses of water per day. How much you should actually drink is more individualized than you might think.
The Institute of Medicine (IOM) recommends that men drink at least 101 ounces of water per day, which is a little under 13 cups. They say women should drink at least 74 ounces, which is a little over 9 cups.
Still, the answer to exactly how much water you should drink isn’t so simple.
While the eight glasses rule is a good start, it isn’t based on solid, well-researched information.
Your body weight is made up of 60 percent water. Every system in your body needs water to function. Your recommended intake is based on factors including your sex, age, activity level, and others, such as if you’re pregnant or breastfeeding.
Adults
The current IOM recommendation for people ages 19 and older is around 131 ounces for men and 95 ounces for women. This refers to your overall fluid intake per day, including anything you eat or drink that contains water, like fruits or vegetables.
Of this total, men should get around 13 cups from beverages. For women, it’s 9 cups.
Children
Recommendations for kids have a lot to do with age.
Girls and boys between 4 and 8 years old should drink 40 ounces per day, or 5 cups.
This amount increases to 56–64 ounces, or 7–8 cups, by ages 9 to 13 years.
For ages 14 to 18, the recommended water intake is 64–88 ounces, or 8–11 cups.
Women of reproductive age
If you’re pregnant or breastfeeding, your recommendations change.
Pregnant women of all ages should aim to get 80 ounces, or ten 8-ounce glasses of water, each day.
Breastfeeding women may need to up their total water intake to 104 ounces, or 13 cups.
| Demographic | Daily recommended amount of water (from drinks) |
| children 4–8 years old | 5 cups, or 40 total ounces |
| children 9–13 years old | 7–8 cups, or 56–64 total ounces |
| children 14–18 years old | 8–11 cups, or 64–88 total ounces |
| men, 19 years and older | 13 cups, or 104 total ounces |
| women, 19 years and older | 9 cups, or 72 total ounces |
| pregnant women | 10 cups, or 80 total ounces |
| breastfeeding women | 13 cups, or 104 total ounces |
Other considerations
You may also need to drink more water if you live in a hot climate, exercise often, or have a fever, diarrhea, or vomiting.
Add an additional 1.5 to 2.5 cups of water each day if you exercise. You may need to add even more if you work out for longer than an hour.
You may need more water if you live in a hot climate.
If you live at an elevation greater than 8,200 feet above sea level, you may also need to drink more.
When you have a fever, vomiting, or diarrhea, your body loses more fluids than usual, so drink more water. Your doctor may even suggest taking drinks with electrolytes to keep your electrolyte balance more stable.