Daily Water Needs
How Many Liters Should a Woman Drink a Day?
The published reference for women is about 2.7 liters of water a day, but that number includes food. Here is what it means in drinks, ounces and cups, what changes it, and where the sources go quiet.
The National Academies put adequate total water for women at about 2.7 liters a day (91 fl oz), from all drinks and food. About 80 percent usually comes from drinks, roughly 2.2 liters (73 fl oz, calculated). It is a reference for healthy, sedentary women in temperate climates, not a quota; thirst guides most healthy people. For an emergency supply, store 1 gallon, about 3.8 liters, per person per day.
What you’ll learn
The short version
How many liters a woman should drink a day has a reference answer rather than a personal rule: about 2.7 liters of total water from drinks and food, of which roughly 2.2 liters usually comes from drinks.
- Women: about 2.7 L (91 fl oz) of total water a day, an adequate intake level from the National Academies (2004).
- About 80 percent from drinks, which is roughly 2.2 L or 73 fl oz (calculated); the rest from food.
- U.S. women drank an average of 43 oz of plain water a day in 2015–2018, about 1.3 L (CDC).
- No source checked for this page publishes a liter figure for pregnancy or breastfeeding, so none is printed here.
- Emergency storage: at least 1 gallon per person per day, for drinking and sanitation (CDC, Ready.gov).
Step 1
How many liters a woman should drink a day: the reference figure
How many liters a woman takes in on an adequate day is about 2.7 liters of total water, the adequate intake level the National Academies set for adult women in 2004.
The National Academies of Sciences, Engineering, and Medicine set the Dietary Reference Intakes used in the United States and Canada. Its 2004 water report found that “women who appear to be adequately hydrated consume an average of approximately 2.7 liters (91 ounces) of total water — from all beverages and foods — each day,” and that men average about 3.7 liters. The panel said these values represent adequate intake levels.
An adequate intake is not a minimum for survival and not a target to hit. It describes the average intake of healthy people who appear well hydrated. The release adds that the reference level “covers the expected needs of healthy, sedentary people in temperate climates,” and that on a daily basis, fluid intake driven by thirst and the habitual consumption of beverages at meals is sufficient for the average person to maintain adequate hydration.
“Total water” is the report’s term for every source of water: plain water, every other beverage, and the moisture in food. The panel used it, in its own words, “to avoid confusion with drinking water only.” That is the main reason the 2.7-liter figure can sound larger than what a woman actually pours into a glass.
For the general question for any adult, see how much water a person should drink a day; for men’s figures, see the companion guide on how much water a man should drink a day.
Step 2
How many liters of drinks a woman needs, and how many come from food
The liters of drinks in a woman’s reference total come to roughly 2.2 liters a day, because the National Academies report that about 80 percent of total water comes from drinking water and beverages.
The release says: “About 80 percent of people’s total water comes from drinking water and beverages — including caffeinated beverages — and the other 20 percent is derived from food.” Applied to the women’s reference as plain arithmetic, that split gives about 2.2 liters from drinks and about 0.5 liters from food.
| Part of the reference | Liters | Fluid ounces |
|---|---|---|
| Total water, published | About 2.7 L | About 91 fl oz |
| From drinks, about 80% Calculated | About 2.2 L | About 73 fl oz |
| From food, about 20% Calculated | About 0.5 L | About 18 fl oz |
“Drinks” here means every beverage, not just water. The National Academies list juice, milk, coffee, tea and soda among the ways people get water, and the panel concluded that caffeinated beverages “can contribute as much as noncaffeinated options” to daily hydration. The CDC’s guidance on water and healthier drinks says plain drinking water counts toward the daily total, and that foods with high water content, such as many fruits and vegetables, also add to fluid intake.
The 80 / 20 split is an average across people; a diet rich in fruit, soup and vegetables supplies more from food, and a mostly dry one less.
Step 3
A woman’s daily water in liters, ounces, cups and bottles
A woman’s daily reference water converts with fixed arithmetic: 2.7 liters is about 91 fluid ounces, 11.4 eight-ounce cups or 5.4 standard 16.9-ounce bottles, and the drinks share is about 9 cups.
The conversions use 33.814 fl oz per liter, 8 fl oz per cup, 16.9 fl oz per common single-serve bottle and 128 fl oz per U.S. gallon. Bottle sizes vary, so check your own labels.
| Amount and source | Liters | Fluid ounces | 8-oz cups | 16.9-oz bottles |
|---|---|---|---|---|
| Average plain water, U.S. women (CDC) | 1.3 | 43 | 5.4 | 2.5 |
| Eight 8-oz glasses (habit, not guidance) | 1.9 | 64 | 8 | 3.8 |
| Women, from drinks (National Academies) | 2.2 | 73 | 9.1 | 4.3 |
| Women, total water (National Academies) | 2.7 | 91 | 11.4 | 5.4 |
| Fluid, normally active person (Ready.gov) | 2.8 | 96 | 12 | 5.7 |
| Stored per person per day (CDC, Ready.gov) | 3.8 | 128 | 16 | 7.6 |
The eight-glass habit, 1.9 liters, sits a little below the drinks share of the reference. It is not a National Academies rule: the panel chair, Lawrence Appel, said in 2004, “We don’t offer any rule of thumb based on how many glasses of water people should drink each day because our hydration needs can be met through a variety of sources in addition to drinking water.” The CDC does not set a glass count either; it says daily water intake recommendations vary by age, sex, pregnancy status, activity level and breastfeeding status.
More conversions for every reference are in the guides to how many liters of water a day, how many ounces of water a day and how many bottles of water a day.
Step 4
How many liters of plain water the average woman actually drinks
The liters of plain water the average U.S. woman actually drinks come to about 1.3 a day: CDC analysis of the 2015–2018 national nutrition survey puts women’s average at 43 ounces of plain water.
The CDC’s water consumption fast facts report a mean of 43 ounces of plain water a day for adult women and 44 ounces for adult men, from a single 24-hour dietary recall in the National Health and Nutrition Examination Survey. Plain water there means tap, fountain, cooler, bottled and spring water; coffee, tea, milk and juice are not included.
A woman’s daily water figures, in liters
Bars scaled to one U.S. gallon, about 3.8 liters. Liters converted from ounces, and the drinks share, are calculated.
The gap between 1.3 liters of plain water and the 2.2-liter drinks share is normally filled by other beverages. That is why a plain-water total alone cannot show whether a woman is drinking enough. The CDC also reports that plain water intake was significantly lower in older adults, so an older woman’s habit may look different again; the CDC figures for age are not split by sex, so this page does not print one.
Step 5
When a woman needs more than the reference liters
A woman needs more than the reference liters when she is very active, in heat or ill, but the only published multiplier in the sources checked here is Ready.gov’s statement that water needs can double in very hot temperatures.
The CDC says your body needs more water when you are in hot climates, more physically active, running a fever, or having diarrhea or vomiting. The National Academies say temporary underconsumption can happen with heat exposure, high physical activity or reduced food and fluid intake, and that “very active individuals who are continually exposed to hot weather often have daily total water needs of six liters or more, according to several studies.” That six-liter observation is from the panel’s summary of studies; it is not a separate reference for women.
Ready.gov, writing for emergencies, gives the one multiplier: “In very hot temperatures, water needs can double.” As plain arithmetic, doubling Ready.gov’s own figure of about ¾ of a gallon of fluid a day gives 1.5 gallons, about 5.7 liters, and doubling the 1-gallon storage allowance gives 2 gallons, about 7.6 liters, per person per day (all calculated). Those are planning numbers for a hot-weather emergency supply, not drinking targets.
No source checked here publishes a liter figure for a woman’s illness, exercise session or hot day. The thirst rule still applies to most healthy people: the National Academies panel’s summary was that “the vast majority of healthy people adequately meet their daily hydration needs by letting thirst be their guide.”
Follow your clinician first. If a clinician has told you to limit fluids, for a heart or kidney condition or any other reason, the reference does not apply to you. The panel set no upper limit for water, but noted that drinking water in excessive amounts, by some athletes during strenuous activity and some people with certain psychiatric disorders, can be life-threatening, though highly unusual.
Step 6
How many liters a woman should drink when pregnant or breastfeeding
How many liters a woman should drink when pregnant or breastfeeding is not stated in any source checked for this page; the CDC says recommendations vary with pregnancy and breastfeeding status, and Ready.gov says nursing mothers may need more water.
The CDC lists pregnancy status and breastfeeding status among the factors that change daily water intake recommendations, without giving a figure on that page. Ready.gov says children, nursing mothers and sick people may need more water, again without a volume. The National Academies news release used here gives the adult women’s figure only.
This site does not estimate, convert or extend a figure that its sources do not publish, so no pregnancy or breastfeeding number appears on this page. The right person to give one is the clinician caring for you, who can also account for heat, activity and any condition that changes your needs.
For an emergency supply. Ready.gov’s note that nursing mothers may need more water is a reason to store above the 1-gallon minimum for a household that includes one. The sources give no extra amount, so many households simply plan toward the CDC’s 2-week supply, which gives more room either way.
Step 7
How many liters of emergency water to store for a woman
The liters of emergency water to store for a woman, as for any person, are at least 1 gallon, about 3.8 liters, per day for drinking and sanitation, for at least 3 days and ideally 2 weeks.
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 gives the same gallon for drinking and sanitation and adds: never ration drinking water unless ordered to do so by authorities.
| Household | 3 days | 2 weeks | 2-week weight |
|---|---|---|---|
| 1 person | 3 gal (about 11.4 L) | 14 gal (about 53 L) | About 117 lb |
| 2 people | 6 gal (about 22.7 L) | 28 gal (about 106 L) | About 233 lb |
| 4 people | 12 gal (about 45.4 L) | 56 gal (about 212 L) | About 466 lb |
The stored gallon is larger than the drinking reference because it also covers hygiene and cooking, and because the coffee, juice and milk that normally supply part of a woman’s water may not be available in an outage. To size a supply for your household, the emergency water storage calculator works out gallons and weight, and the guide to how much water per person per day to store walks through the planning. Use only clean, food-grade containers intended for drinking water.
Questions
Common questions about how many liters a woman should drink
These are the questions people most often ask about women’s daily water.
The National Academies put adequate total water for women at about 2.7 liters a day from all drinks and food, with roughly 2.2 liters usually coming from drinks (calculated). Most healthy women meet their needs by letting thirst guide them.
Two liters of drinks is a little under the roughly 2.2-liter drinks share of the women’s reference (calculated), and food usually adds about half a liter more. The reference describes healthy, sedentary women in temperate climates; heat, activity and illness raise needs.
About 91 fluid ounces of total water a day from drinks and food, the National Academies reference, with roughly 73 ounces from drinks (calculated). U.S. women actually drank an average of 43 ounces of plain water a day in 2015–2018, according to the CDC.
None of the sources used on this page publishes a figure. The CDC says recommendations vary with pregnancy and breastfeeding status, and Ready.gov says nursing mothers may need more water. Ask the clinician caring for you.
Store at least 1 gallon, about 3.8 liters, 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 about 11.4 liters for 3 days and about 53 liters 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.
- 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; adequate intake levels; about 80 percent from drinking water and beverages, including caffeinated ones; reference covers healthy, sedentary people in temperate climates; thirst as a guide; very active people continually in hot weather often need six liters or more; no glass-count rule of thumb; no upper limit set. Checked October 2026.
- Centers for Disease Control and Prevention, “About Water and Healthier Drinks” (page dated March 5, 2026). cdc.gov — recommendations vary by age, sex, pregnancy status, activity level and breastfeeding status; more water needed in hot climates, with more activity, fever, diarrhea or vomiting; water-rich foods add to intake. Checked October 2026.
- Centers for Disease Control and Prevention, “Fast Facts: Data on Water Consumption” (page dated January 19, 2024). cdc.gov — U.S. adult women drank an average of 43 ounces of plain water a day in 2015–2018; plain water intake significantly lower in older adults. 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.
- 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.
- 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.
