Daily Water Needs
How Much Water Does the Average Person Drink a Day?
The national survey answer is smaller than most people guess. Here is what U.S. adults and children actually drink in plain water, how it changes with age, and why the average is not a target.
U.S. adults drank an average of 44 ounces of plain water a day in 2015–2018, and children and teens aged 2 to 19 drank an average of 23 ounces, according to CDC national survey data. That counts plain water only. Other drinks and food add more: the National Academies’ reference for total water is about 91 fl oz a day for women and 125 fl oz for men. For an emergency supply, store 1 gallon, 128 fl oz, per person per day.
What you’ll learn
The short version
How much water the average person drinks a day, in plain water, is 44 ounces for U.S. adults and 23 ounces for U.S. children and teens, based on CDC analysis of the 2015–2018 national nutrition survey.
- Adults 20 to 39 drank the most plain water, 51 oz a day; adults 60 and older drank the least, 36 oz (CDC).
- Men and women drank almost the same amount: 44 oz and 43 oz (CDC).
- Plain water is only part of daily water. Other drinks and food count toward the National Academies’ reference of about 91 fl oz for women and 125 fl oz for men.
Step 1
How much water the average person drinks: the national survey figure
How much water the average American adult drinks, measured as plain water, is 44 ounces a day, according to CDC analysis of the National Health and Nutrition Examination Survey for 2015–2018.
The Centers for Disease Control and Prevention (CDC), the federal public-health agency, publishes the figure on its water consumption fast facts page. It reports that during 2015–2018, U.S. children and adolescents drank an average of 23 ounces of plain water daily, and U.S. adults drank an average of 44 ounces.
The National Health and Nutrition Examination Survey (NHANES) is the CDC’s long-running survey of a nationally representative sample of people. For these water figures, the CDC notes that the data came from a single 24-hour dietary recall and that the estimates were weighted to represent the U.S. population.
The CDC is specific about what counts as plain water in this measure: plain tap water, water from a drinking fountain, water from a water cooler, bottled water and spring water. Coffee, tea, milk, juice and soft drinks are not part of the 44-ounce figure, even though they contain water.
| Group | Plain water, ounces a day (CDC) | In 8-oz cups Calculated |
|---|---|---|
| All adults, 20 and older | 44 | 5.5 |
| All children and adolescents, 2 to 19 | 23 | 2.9 |
An average is a midpoint, not anyone’s typical day; the CDC summary reports means and standard errors, not the full spread. For the separate question of how much a person should drink, see how much water a person should drink a day.
Step 2
How much water the average person drinks at each age
How much water the average person drinks rises through childhood and falls with age in adulthood: from 13 ounces a day at ages 2 to 5 up to 51 ounces in adults 20 to 39, then down to 36 ounces at 60 and older.
The CDC marks both older adult groups as significantly lower than ages 20 to 39, and both younger child groups as significantly lower than teens.
Average plain water a day, by age, in fluid ounces
CDC analysis of NHANES 2015–2018. Bars scaled to 51 oz.
The gap between the youngest and oldest adult groups is 15 ounces a day (calculated), close to two cups. The CDC does not explain it, and this page does not guess.
For children, the measure leaves out milk and other drinks, so a preschooler’s 13 ounces of plain water says nothing about how much fluid that child needs. Questions about a particular child belong with the clinician who knows the child.
Step 3
How much water the average man and woman drink, and other differences
How much water the average man and the average woman drink in plain water is nearly identical, 44 and 43 ounces a day, but the CDC found larger differences by income, education and weight status.
The CDC summary states that plain water consumption varies by age, race and ethnicity, and socioeconomic status. Among adults, it reports significantly lower plain water intake in older adults, in non-Hispanic Black adults compared with non-Hispanic White adults, in adults with lower income and less education, and in adults without obesity. The full adult table is below, exactly as published.
| Characteristic | Mean, ounces a day |
|---|---|
| Male (reference) | 44 |
| Female | 43 |
| White, non-Hispanic (reference) | 44 |
| Black, non-Hispanic | 39* |
| Hispanic | 44 |
| Asian, non-Hispanic | 45 |
| Income below 130% of the poverty line | 40* |
| Income 130% to under 350% | 42* |
| Income 350% or more (reference) | 47 |
| Less than high school | 36* |
| High school graduate, GED or equivalent | 39* |
| Some college | 46 |
| College graduate or higher (reference) | 48 |
| Underweight or healthy weight | 42* |
| Overweight | 41* |
| Obesity (reference) | 47 |
The sex difference is one ounce, and the CDC does not mark it as significant, even though the reference figures for total water differ for men and women.
The children’s table shows a similar pattern by age, race and ethnicity, household income, head-of-household education and weight status. Boys averaged 24 ounces and girls 23.
These are survey associations. The CDC does not say any group drinks too little, and plain water alone does not show total hydration.
Step 4
What the average person drinks besides plain water
What the average person drinks besides plain water counts toward daily water too: the CDC says intake comes mostly from water and other beverages, and that water-rich foods add to it.
The CDC’s guidance on water and healthier drinks says daily water intake is mostly from water and other beverages, and that foods, especially those with high water content such as many fruits and vegetables, can also add to fluid intake. It says plain drinking water counts toward the daily total.
The same page lists plain coffee or tea, sparkling water, milk and 100% juice among healthier drink options. All of them contain water, and none of them is in the 44-ounce plain-water average.
Caffeine does not cancel a drink out. The National Academies panel that set the U.S. and Canadian reference values concluded that “caffeinated beverages can contribute as much as noncaffeinated options” to daily hydration, finding no convincing evidence that caffeine causes cumulative body water deficits.
Plain water versus total water. The CDC survey figure measures plain water. The National Academies reference measures total water: every drink plus the moisture in food. The two are different measurements, so comparing them directly overstates any gap.
Step 5
How much water the average person drinks compared with the reference amount
How much water the average person drinks, 44 ounces of plain water, is below the drinks share of the National Academies reference, about 73 fl oz for women and 100 fl oz for men, because other beverages make up the rest.
In its 2004 water report, the National Academies of Sciences, Engineering, and Medicine found that women who appear adequately hydrated consume an average of about 2.7 liters (91 ounces) of total water a day and men about 3.7 liters (125 ounces), and said these values represent adequate intake levels. About 80 percent of total water comes from drinking water and beverages and about 20 percent from food.
| Measure | Women | Men |
|---|---|---|
| Average plain water (CDC) | 43 oz | 44 oz |
| Reference, from drinks Calculated | About 73 fl oz | About 100 fl oz |
| Reference, total water (National Academies) | About 91 fl oz (2.7 L) | About 125 fl oz (3.7 L) |
The panel was clear that its numbers are not a quota: “The vast majority of healthy people adequately meet their daily hydration needs by letting thirst be their guide.” It also said the reference level covers the expected needs of healthy, sedentary people in temperate climates, and that people who are very physically active or who live in hot climates may need more.
Read together, the sources say the average adult drinks about 44 ounces of plain water and gets the rest from other drinks and food; neither says whether a given person drinks enough. To see the reference for your own situation in ounces, liters or cups, the water intake calculator shows the published figures side by side, and the guide to ounces of water a day converts every reference.
Follow your clinician first. If a clinician has told you to limit fluids, for a heart or kidney condition or any other reason, neither the average nor the reference applies to you. For pregnancy, breastfeeding and children, ask the clinician who knows the person.
Step 6
The average person’s daily water in cups, bottles and liters
The average person’s daily plain water converts with fixed arithmetic: 44 ounces is 5.5 eight-ounce cups, about 2.6 standard 16.9-ounce bottles, or about 1.3 liters.
The conversions use 8 fl oz per cup, 16.9 fl oz per common single-serve bottle, 0.0296 liters per fluid ounce and 128 fl oz per U.S. gallon. Bottle sizes vary.
| Group (CDC average) | Fluid ounces | 8-oz cups | 16.9-oz bottles | Liters | Share of 1 gallon |
|---|---|---|---|---|---|
| Children 2 to 5 | 13 | 1.6 | 0.8 | 0.4 | 10% |
| All children and teens | 23 | 2.9 | 1.4 | 0.7 | 18% |
| Adults 60 and older | 36 | 4.5 | 2.1 | 1.1 | 28% |
| All adults | 44 | 5.5 | 2.6 | 1.3 | 34% |
| Adults 20 to 39 | 51 | 6.4 | 3.0 | 1.5 | 40% |
The familiar eight 8-ounce glasses add up to 64 ounces, so the average adult’s plain water is about 20 ounces short of that habit (calculated). The National Academies panel offered no glass-count rule of thumb, so falling short of eight glasses is not, on its own, a sign of a problem. Separate guides cover how many bottles of water a day and how many liters of water a day in detail.
Step 7
How much water the average person needs stored for an emergency
How much water the average person needs stored for an emergency is at least 1 gallon, 128 fl oz, per day, covering drinking and sanitation, for at least 3 days and ideally 2 weeks.
An emergency supply is sized differently from a drinking habit. The CDC’s emergency water page says to store at least 1 gallon of water per person, per day for 3 days, for drinking, cooking, brushing teeth and other uses, and to try to store a 2-week supply if possible. Ready.gov says a normally active person needs about ¾ of a gallon of fluid daily, from water and other beverages, and that in very hot temperatures water needs can double.
The stored gallon is about three times the average adult’s plain-water habit (calculated: 128 divided by 44 is 2.9), because in an outage other drinks may be unavailable and the supply also covers hygiene.
| Household | 3 days | 2 weeks | 2-week weight |
|---|---|---|---|
| 1 person | 3 gal | 14 gal | About 117 lb |
| 2 people | 6 gal | 28 gal | About 233 lb |
| 4 people | 12 gal | 56 gal | About 466 lb |
Ready.gov adds that children, nursing mothers and sick people may need more water, and that you should never ration drinking water unless ordered to do so by authorities. To size your own supply, the emergency water storage calculator works out gallons and weight for your household, and the guide to how much water per person per day to store walks through the planning. For the household side of the numbers, see how much water the average person uses a day and, in a coming guide, how much water the average household uses.
Questions
Common questions about how much water the average person drinks
Common questions about average daily water intake.
U.S. adults drank an average of 44 ounces of plain water a day in 2015–2018, and children and teens aged 2 to 19 drank an average of 23 ounces, according to CDC analysis of national survey data. Other drinks and food add more water on top of that.
The National Academies reference is about 91 fluid ounces of total water a day for women and 125 for men, from all drinks and food, with roughly 73 and 100 ounces from drinks (calculated). The CDC’s 44-ounce average counts plain water only, so the two figures measure different things.
In plain water, barely. The CDC reports 44 ounces a day for men and 43 for women in 2015–2018. The reference for total water is higher for men, about 125 fluid ounces against 91 for women.
On average, yes. The CDC reports 51 ounces of plain water a day for adults 20 to 39, 43 ounces for ages 40 to 59 and 36 ounces for adults 60 and older, and marks both older groups as significantly lower than the youngest.
Store at least 1 gallon per person per day for drinking and sanitation, for at least 3 days, and a 2-week supply if possible, according to the CDC and Ready.gov. That is 3 gallons per person for 3 days and 14 gallons for 2 weeks (calculated).
Sources
Where these figures come from
Every figure on this page is quoted from, or calculated from, one of these sources, checked in October 2026.
- Centers for Disease Control and Prevention, “Fast Facts: Data on Water Consumption” (page dated January 19, 2024). cdc.gov — mean daily plain water intake from NHANES 2015–2018: 44 ounces for adults 20 and older and 23 ounces for children and adolescents 2 to 19; Tables 1 and 2 by age, sex, race and ethnicity, income, education and weight status; plain water definition; single 24-hour dietary recall, weighted estimates. Checked October 2026.
- Centers for Disease Control and Prevention, “About Water and Healthier Drinks” (page dated March 5, 2026). cdc.gov — intake mostly from water and other beverages, with water-rich foods adding; plain water counts toward the daily total; lists of lower-calorie and nutrient-providing drinks. Checked October 2026.
- National Academies of Sciences, Engineering, and Medicine, news release on dietary reference intakes for water, salt and potassium (February 11, 2004). nationalacademies.org — about 2.7 L (91 oz) of total water a day for women and 3.7 L (125 oz) for men; adequate intake levels; about 80 percent from drinks; thirst as a guide; caffeinated beverages count; no glass-count rule of thumb; reference covers healthy, sedentary people in temperate climates. Checked October 2026.
- Centers for Disease Control and Prevention, “How to Create an Emergency Water Supply.” cdc.gov — at least 1 gallon per person per day for 3 days; a 2-week supply if possible. Checked October 2026.
- Ready.gov, “Water.” ready.gov — about ¾ gallon of fluid daily for a normally active person; at least 1 gallon per person per day for drinking and sanitation; needs can double in very hot temperatures; children, nursing mothers and sick people may need more; never ration drinking water unless ordered to. Checked October 2026.
- U.S. Geological Survey, “Water Density.” usgs.gov — water at 70°F weighs 62.300 pounds per cubic foot; converted to about 8.33 pounds per U.S. gallon (calculated) for every weight on this page. Checked October 2026.
