How Much Water Should a Woman Drink? Women's Hydration Statistics

These are Adequate Intakes, not hard targets: the amount that healthy people typically consume, set by the National Academies in 2004. They count water from food as well as drinks.

1. 91 fl oz

   The National Academies set the Adequate Intake for adult women at 2.7 liters (about 91 fl oz) of total water a day, counting water from food as well as drinks.

   National Academies of Sciences, Engineering, and Medicine, 2005Copy statLink

2. ~9 cups

   About 2.2 liters (74 fl oz, roughly 9 cups) of a woman’s 2.7-liter daily Adequate Intake is expected to come from beverages, including plain water.

   National Academies of Sciences, Engineering, and Medicine, 2005Copy statLink

3. 101 fl oz

   During pregnancy the Adequate Intake rises to 3.0 liters (about 101 fl oz) of total water a day, about 2.3 liters (78 fl oz) of it from drinks.

   National Academies of Sciences, Engineering, and Medicine, 2005Copy statLink

4. 128 fl oz

   While breastfeeding, the Adequate Intake is 3.8 liters (about 128 fl oz) of total water a day, about 3.1 liters (105 fl oz) of it from drinks, and 1.1 liters (37 fl oz) more than for other adult women.

   National Academies of Sciences, Engineering, and Medicine, 2005Copy statLink

5. 20%

   About 20% of the water people take in comes from food rather than drinks, according to the National Academies.

   National Academies, 2004Copy statLink

6. 35%

   US guidance for women’s total water (2.7 liters a day) is 35% higher than Europe’s (2.0 liters a day).

   Both are total water from food and drinks; EFSA’s value assumes moderate temperature and activity. Our calculation: 2.7 ÷ 2.0 = 1.35.

   National Academies of Sciences, Engineering, and Medicine, 2005 · European Food Safety Authority, 2010Copy statLink

Federal survey data (NHANES) on what US women reported eating and drinking over 24 hours.

1. 43 oz

   US women drink an average of 43 ounces of plain water a day, about 5 cups; men drink 44.

   Adults 20 and older, NHANES 2015–2018. The guideline of about 74 oz a day from drinks counts all drinks, not just plain water.

   Centers for Disease Control and Prevention, 2024Copy statLink

2. 93 fl oz

   US women aged 20 and over took in an average of 2.75 liters (about 93 fl oz) of total water a day from food and drinks in 2009–2012.

   NHANES 2009–2012; excludes pregnant and breastfeeding women.

   CDC National Center for Health Statistics, 2016Copy statLink

3. 85 fl oz

   Women 60 and older averaged 2.51 liters (about 85 fl oz) of total water a day, the lowest of any adult women’s age group.

   NHANES 2009–2012. Women 20–39 averaged 2.78 liters and women 40–59 2.90 liters.

   CDC National Center for Health Statistics, 2016Copy statLink

4. 34%

   Plain water made up only 34% of US women’s total daily water intake (food and drinks combined) in 2009–2012, and 30% of men’s.

   CDC National Center for Health Statistics, 2016Copy statLink

5. 51%

   Water accounted for 51.2% of all the nonalcoholic beverages US adults aged 20 and over drank in 2015–2018.

   NHANES 2015–2018. Women: 54.0%; men: 48.2%.

   CDC National Center for Health Statistics, 2020Copy statLink

What the evidence does and doesn’t say. We only include claims a public health body or peer-reviewed review has made.

1. 7%

   About 7% of women and 11% of men in the US will have a kidney stone in their lifetime.

   Endotext (NCBI Bookshelf), 2026Copy statLink

2. Thirst

   The National Academies concluded that most healthy people meet their daily water needs by letting thirst guide them, along with drinks at meals.

   National Academies, 2004Copy statLink

3. 75%

   The viral claim that "75% of Americans are chronically dehydrated" circulated in a 2011 chain email; Snopes rates its "chronically dehydrated" premise False.

   Snopes, 2001, updatedCopy statLink

4. 0

   A 2002 review in the American Journal of Physiology found no scientific studies supporting the advice to drink eight 8-oz glasses of water a day.

   The review’s conclusion covers healthy, largely sedentary adults in a temperate climate.

   American Journal of Physiology, 2002Copy statLink

Sources

1. National Academies of Sciences, Engineering, and Medicine (2005). Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate.
2. National Academies (2004). Report Sets Dietary Intake Levels for Water, Salt, and Potassium to Maintain Health and Reduce Chronic Disease Risk.
3. European Food Safety Authority (2010). Scientific Opinion on Dietary Reference Values for water.
4. Centers for Disease Control and Prevention (2024). Fast Facts: Data on Water Consumption (NHANES 2015–2018).
5. CDC National Center for Health Statistics (2016). Daily Water Intake Among U.S. Men and Women, 2009–2012 (NCHS Data Brief No. 242).
6. CDC National Center for Health Statistics (2020). Nonalcoholic Beverage Consumption Among Adults: United States, 2015–2018 (NCHS Data Brief No. 376).
7. Endotext (NCBI Bookshelf) (2026). Nephrolithiasis (Maalouf NM).
8. Snopes (2001, updated). Do You Need Eight Glasses of Water Per Day? (fact check).
9. American Journal of Physiology (2002). "Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8 x 8"?.
10. American College of Obstetricians and Gynecologists (2026). How much water should I drink during pregnancy? (Ask ACOG).