How Much Water Should You Drink a Day?

How much water you should drink each day depends on several factors, but generally healthy people need 4 to 6 cups of plain water each day, depending on what other beverages and foods they eat.

Getting enough water daily is essential to staying healthy. The widespread advice is to drink 8 glasses (64 ounces) of water daily, but this recommendation does not apply to everyone. Daily water intake recommendations vary based on age, sex, activity level, pregnancy, breastfeeding, and health status.

Read more about how much water you should drink a day, why it is important to overall health, and signs of adequate hydration.

How Much Water Do You Need Per Day?

The amount of water your body needs varies and depends on how much you exert yourself and how much you urinate or sweat. For most healthy adults, the volume of fluids to prevent dehydration is:

• 13 cups for males
• 9 cups for females

You can get water through other beverages or foods high in water content, like fruits and vegetables. In the United States, some estimates show that about 22% of our water intake comes from our food.

Adequate hydration, or consuming enough fluids, is essential for your health. Hydration impacts skin health, neurological function, digestion, and kidney function.

People lose (and must replace) water throughout the day from sweating, breathing, urinating, and having bowel movements. For healthy people, the vasopressin hormone (also called the antidiuretic hormone) and the kidneys help to regulate fluid loss. Thirst tells your body to drink more fluids.

Most people will lose a little over 16 ounces (or 500 milliliters) of fluid through urine per day. That means you need to drink more than 16 ounces (2 cups) of fluids to replace the urine loss. If your urine is very pale and has little to no odor, this is a good indication that you are well-hydrated. Darker, concentrated urine can indicate dehydration.

Recommended Water Intake by Age

There is no exact amount of water for each age group, but there are general guidelines for moderate exercise and temperature.

• Infants: Experts do not recommend water for infants before 6 months of age. Between 6 and 12 months of age, 1/2 cup to 1 cup (4 to 8 ounces) is recommended.
• Children: One cup to 5 cups of water is recommended for children, along with 2 to 3 cups of milk.
• Adolescents: Seven to 8 cups of water is recommended for adolescents.
• Adults. Total water needs are estimated at 3.7 liters (15.5 cups) for adult males and 2.7 liters (11.5 cups) for adult females. This includes water from all sources—plain water, water in other beverages, and water in foods.
• Pregnancy: According to the American College of Obstetricians and Gynecologists (ACOG), pregnant people should drink 8–12 cups (64–96 ounces) of water daily. This amount is in addition to water they may get from foods and other beverages.
• Breastfeeding: To compensate for the extra water used to make breast milk, 16 cups of water are recommended daily, which can come from food, beverages, and drinking water.
• Older adults: The National Academy of Medicine suggests an adequate intake of about 13 cups of daily fluids for males and 9 cups for females aged 51 and older. With a higher risk of dehydration and health issues, getting enough water is essential for older adults.

How Much Water Should You Drink if You Exercise?

Whether you exercise for recreation or you're an athlete, proper hydration is important for performance and overall health. Water regulates body temperature and lubricates your joints. It helps transport nutrients to give you energy and keep you healthy.

The American Council on Exercise has suggested the following basic guidelines for drinking water before, during, and after exercise:

• Drink 17 to 20 ounces of water two to three hours before exercising.
• Drink 8 ounces of water 20 to 30 minutes before starting to exercise or during your warm-up.
• Drink 7 to 10 ounces of water every 10 to 20 minutes during exercise.
• Drink 8 ounces of water no more than 30 minutes after you stop exercising.

One very small study of eight males found drinking larger, less frequent water boluses (dosages) or drinking smaller, more frequent water boluses are both reasonable strategies to promote adequate hydration and limit body water loss during heavy-intensity work in the heat.

Depending on how long and hard you exercise, electrolytes may or may not be needed. Electrolytes include salt and minerals such as potassium, phosphate, calcium, and magnesium. Maintaining electrolyte balance maximizes the performance of the body’s muscles, organs, and joints.

A sports drink that includes both carbohydrates and electrolytes is recommended for exercise sessions lasting longer than 60–90 minutes. One study found hypotonic carbohydrate-electrolyte drinks ingested continuously during exercise provided the greatest benefit to hydration. These drinks are lower in salt and sugar.

What Affects the Amount of Water You Need?

Factors that affect how much water you need include:

• Body size
• Sweat rate
• The heat and humidity in your environment
• Your clothing
• How long and hard you are exercising

You may need more water if you:

• Live or work in hot climates
• Are physically active and sweat a lot
• Have a fever, diarrhea, or vomiting
• Are pregnant or breastfeeding

It's possible to get too much water if you have certain health conditions, such as:

• Thyroid disease
• Kidney or liver problems
• Heart problems

With these conditions, water intake may need to be lowered or closely monitored.

If you're taking medications that make you retain water, like nonsteroidal anti-inflammatory drugs (NSAIDs), opiate pain medications, and some antidepressants you may need to decrease how much water you drink.

What Are the Benefits of Drinking Water?

Water is essential to health; humans can only survive for a few days without it. Water makes up 75% of body weight in infants and 55% of body weight in older adults. Every cell in your body requires water to function and repair itself.

The benefits of drinking water include:

• Avoiding dehydration
• Helping to regulate your body temperature and blood pressure
• Lubricating and cushioning your joints
• Protecting your spine and other body tissues
• Ridding the body of waste through sweat, urine, and bowel movements
  
• Preventing urinary tract infections, kidney stones, and constipation

Does Drinking Water Help You Lose Weight?

The advice to drink water for weight loss is widespread. One study found that 30% of adults in the United States who tried to lose weight stated that they drank a lot of water. A smaller research study showed that 59% of adults applied drinking water frequently as a weight loss or weight control practice.

Some people believe that drinking water in place of sugar-containing beverages such as soda and juice may prevent overweight and obesity by reducing the total number of calories consumed. Further, drinking plenty of water can increase the feeling of fullness and reduce hunger in the short term.

However, there's limited evidence that drinking water can help with weight loss or maintaining weight over time. Many studies have shown that more water consumption was not associated with reduced body weight.

The Dietary Guidelines for Americans recommends choosing calorie-free beverages, such as water, as a primary source of hydration over other sugar-sweetened beverages as part of a healthy diet.

Can Other Fluids Help You Stay Hydrated?

There are many other beverages besides water to help you stay hydrated.

Best choice beverages include:

• Low- or no-calorie beverages such as plain coffee, plain tea, sparkling or seltzer water, and flavored waters
• Drinks with calories and other essential nutrients, such as dairy and fortified nondairy milk, 100% fruit and vegetable juices, or smoothies

Other fluids that can help you stay hydrated, but should be limited include:

• Sugar-sweetened beverages, such as soda and fruit drinks
• Caffeinated drinks such as energy drinks, as well as coffees, and teas with added milk and sweeteners
• Drinks with sugar alternatives
• Sports drinks

Sports drinks generally contain carbohydrates, electrolytes, and vitamins. Research indicates that sports drinks may benefit people engaged in vigorous exercise for more than one hour, especially if they are sweating heavily. For most people, regular water is sufficient to stay hydrated during exercise.

How to Tell if You're Hydrated

The easiest way to tell if you're hydrated is to check your urine. If you urinate regularly and it is light to clear in color and does not have a strong odor, you are likely hydrated.

Other signs of hydration may include a regular pulse, firm skin (bounces back when pinched), and adequate moisture in your eyes, mouth, and lips. Drinking water or other fluids regularly throughout the day and eating water-rich foods can help you stay hydrated.

It is easier to identify signs of dehydration than hydration. Being well-hydrated should result in the absence of symptoms such as:

• Excessive thirst
• Dry mouth, eyes, or skin
• Headaches or cognitive impairment
• Confusion, dizziness, or irritability
• Lack of urination or constipation
• Fatigue

Can You Drink Too Much Water?

Although drinking too much water is uncommon in healthy adults, occasionally overhydration can occur in athletes, people with kidney problems, or people taking certain medications that can cause excessive thirst.

Drinking too much water makes it hard for the kidneys to get rid of the excess water. The sodium content of your blood becomes diluted, and cells in the brain and other parts of the body swell with water. This is called hyponatremia, and it can be life-threatening.

Summary

Drinking water is necessary for optimal health. The amount of daily water intake required to stay hydrated can vary depending on your specific needs, health conditions, and lifestyle. You can also consume water and fluids through foods and other beverages. If you live or work in a hot climate or exercise and sweat a lot, consider increasing the number of glasses of water you drink daily.

Frequently Asked Questions

For high-intensity exercise exceeding 45–60 minutes, you should drink 17–20 ounces of water two hours before the start and 7 to 10 ounces of fluid every 10–20 minutes during exercise.

Several formulas across the internet use weight to calculate the amount of water an individual should drink daily. However, this rule doesn't consider the number of fluids you consume through food or other beverages. An easier way to check your hydration status is to examine your urine output and look for a pale yellow color with no odor to indicate hydration.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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By Rebecca Valdez, MS, RDN
Valdez is a registered dietitian nutritionist, health writer, and nutrition consultant. She received her MS degree in nutrition from Columbia University.

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