How Much Water Should I Drink?

Your body contains more water than anything else—about 60% of your total body weight. Water helps regulate your body temperature, transport nutrients, and remove waste. Every day you lose water when you breathe, sweat, urinate, and defecate, and that water needs to be replenished.

How Much Water Should You Drink?

People often wonder how much water they need to drink every day to stay healthy. While that may seem like a simple question, it doesn't necessarily have an easy answer. It depends on some environmental and physical factors that can vary each day.

Also, it's not just the water you're drinking that keeps you hydrated—about 20% of your water intake comes from the foods you eat. The remaining 80% comes from beverages, including water, coffee, tea, milk, and anything liquid.

The Institute of Medicine of the National Academy reviewed years of research evidence on adequate water intake and provided the following recommendations for total daily water intake (including food and beverages) for adults aged 19–50:

Pregnant People

Those who are pregnant need about 13 cups of fluids each day (10 cups from water and beverages), according to the Institute of Medicine. Some people retain extra fluid during their pregnancy and have some swelling, but that doesn't reduce their need for water.

Breastfeeding People

Breastmilk is mostly water, so you'll need to drink extra water or healthy beverages while you're breastfeeding. The Institute of Medicine recommends that all breastfeeding people consume about 13 cups of fluids daily.

Children

Water intake varies among children aged 18 and under and depends on factors like age and sex. The Institute of Medicine recommends the following fluid intakes for children in different age groups:

• Children aged 1–3 years: 5.5 cups per day of total water. This includes about 4 cups of total beverages including drinking water.
• Children aged 4–8 years: 7 cups per day of total water. This includes about 5 cups as total beverages, including drinking water.
• Boys aged 9–13 years: 10 cups per day of total water. This includes about 8 cups as total beverages, including drinking water.
• Boys aged 14–18 years: 14 cups per day of total water. This includes about 11 cups as total beverages, including drinking water.
• Girls aged 9–13 years: 9 cups per day of total water. This includes about 7 cups as total beverages, including drinking water.
• Girls aged 14–18 years: 10 cups per day of total water. This includes about 8 cups as total beverages, including drinking water.

Benefits

There are plenty of good reasons to drink more water. In addition to staying hydrated and maintaining optimal function in the body, drinking more water can also lead to:

• Better physical performance: A 2018 study published in the Journal of the International Society of Sports Nutrition determined that adequate hydration enhanced power, focus, and heart rate recovery time in athletes.
• Fewer headaches: A study conducted in 2011 found that increased water consumption was associated with a decreased frequency of headaches. The researchers recommended increasing water consumption as a potential noninvasive treatment for those with chronic headaches.
• Bowel regularity: While laxatives are considered a helpful treatment for constipation, a 2015 study notes that older adults are often dehydrated because they don't drink enough water, which can cause this condition. Meeting the recommended intake for water consumption can help to promote bowel regularity and increase stool frequency.
• Weight loss: A study published in 2013 showed that water consumption led to a significant decrease in body weight and body mass index (BMI). 50 overweight subjects were instructed to drink 500 ml (2 cups) of water three times a day before each meal, which was more than they had previously been drinking. Results indicated that water consumption increased thermogenesis, or the "thermic effect" of food, to help subjects burn more calories throughout the day.

When You Might Need to Drink More Water

Some people may need to increase their water consumption more so than others depending on how active they are, where they live, and their current health status. Here are some of the factors that can affect how much water you should be drinking in order to stay properly hydrated.

Frequent Exercise

Increased physical activity like exercise or manual labor can increase the amount of fluid lost when you sweat. It's best to drink 2–3 cups of water before your activity begins and continue to hydrate while you're active. You might need 1 cup of water or more every 15 minutes or so if you're working or exercising in extreme temperatures.

Hot Weather

Water is essential for regulating your body temperature, so if you're outside on a hot day or inside without air conditioning, you're going to need more water as you sweat from the heat. Even if you're not active, spending the day in 90-degree temperature conditions could more than double your daily fluid requirement. If you're physically active you may require even more than that.

High Elevations

Air pressure is reduced at higher elevations and compared to being at sea level. People who live at higher altitudes generally lose more fluid each day due to changes in respiration. The higher you go, the greater potential for fluid loss. Be prepared and make sure to bring extra water if you're going for a hike in the mountains.

Illness

If you're sick with a fever, getting dehydrated could make the fever worse. Sip water or other fluids to keep yourself hydrated. Diarrhea can happen for a number of reasons, including infections, irritable bowel syndrome, and inflammatory bowel disorders. But whatever the cause, diarrhea can lead to dehydration. Drink extra fluids while you have diarrhea, and afterward, to remain hydrated.

Hangover

Drinking too much alcohol will lead to a hangover the next day. While one or two alcoholic beverages shouldn't cause a problem, overindulging can result in dehydration, inflammation, a headache, and stomach irritation.

Drink plenty of water while you're recovering from being sick or recuperating from a hangover. And next time you're enjoying alcohol, be sure to hydrate in between drinks as this may help prevent a hangover and even slow your rate of consumption.

Signs You Need to Drink More Water

Most people can gauge their water intake by looking at urine color. If you're getting enough water, your urine will be pale yellow and you'll urinate several times a day. But simply looking at your urine color isn't always the best indicator.

Dietary supplements that contain riboflavin will make your urine bright yellow and certain medications can change the color of your urine as well. If you have any kidney problems or other health conditions, you should talk to your health care provider about how much water to drink.

Here are some signs of dehydration to look out for that may indicate you need to drink more water.

Thirst

Thirst is the desire to drink something. It can be triggered by the loss of fluid volume in and around cells and in the blood. Thirst is your body's way of saying you need water to avoid dehydration.

Thirst has a behavioral component and can be triggered by aromas and flavors, so just thinking about your favorite beverage can make you thirsty.

Bad Breath and Dry Mouth

There are some things that can cause bad breath like eating onions or garlic. But another potential reason is a lack of normal saliva production. Even mild dehydration can reduce saliva flow, so if your bad breath is accompanied by a dry mouth, drinking more water throughout the day can help. It's a smart idea to keep a glass of water by your bedside for nighttime relief, too.

Brain Fog

Water is essential for brain function. Studies show that a loss of about 2% of your body fluids can cause a decline in mental function. If you're having trouble concentrating, it may be time for a water break.

There's probably some potential for dehydration if you're gulping down energy drinks and not drinking extra water when you're more active than usual.

Risks of Drinking Too Much or Too Little

There are risks associated with drinking too little water as well as too much. That's why it's important to stay within your recommended intake based on your age, sex, level of activity, and other factors that play a role.

Dehydration

Dehydration is what happens when your body does not have the amount of water and fluids it needs to function properly. Some people are less inclined to drink water if they're feeling sick or nauseated, while others may simply forget.

Depending on how much fluids have been lost and whether they've been replenished, dehydration can range from mild to moderate to severe. Symptoms of dehydration include:

• Excessive sweating (i.e., exercising in hot weather)
• Fever
• Vomiting or diarrhea
• Frequent or excessive urination (often caused by diabetes or certain medications such as diuretics)

Hyponatremia

Hyponatremia, also known as low blood sodium or water intoxication, is a medical condition that occurs when there is an abnormal amount of sodium in the blood. Adequate levels of blood sodium are important for maintaining blood pressure and ensuring the nerves, muscles, and tissues in the body can function properly.

Low blood sodium can be caused by medical conditions such as heart or kidney failure or liver cirrhosis, and can occur in patients taking diuretics. But hyponatremia can also be a byproduct of overhydration. Drinking too much water overwhelms the kidneys, which dilutes the levels of sodium in the blood.

Overhydration is often exercise-induced and is common among runners and endurance athletes since excessive sweating can throw the blood-sodium concentration out of balance. Symptoms of low blood sodium include:

• Fatigue
• Headache
• Loss of appetite
• Muscle weakness, spasms, or cramps
• Nausea and vomiting
• Confusion, irritability, restlessness 
• Convulsions
• Loss of consciousness
• Brain herniation
• Death

How to Drink More Water

If you think you're not drinking enough water, there a few small changes you can make each day to boost your intake. The following tips can help you ensure you're getting enough H2O.

• Use a refillable water bottle. Refilling the same water bottle throughout the day not only saves a ton of single-use plastic waste but also helps increase water consumption. A 24-ounce bottle contains 3 cups of water, so if you refill your bottle twice you'll likely meet your recommended daily intake. Plus, refillable bottles come in many colors, shapes, sizes, and materials, which can help make drinking water more fun and appealing.
• Set a daily intake goal. Goal-setting is a powerful exercise that can be applied to many aspects of health, including hydration. Set a personal goal to drink at least eight 8-ounce glasses of water per day, and make up for any remaining amount of fluids with other low-calorie beverages like unsweetened fruit and vegetable juices, teas, and electrolyte beverages.
• Pace yourself. It's not recommended to chug all your fluids at once. Instead, try spacing out your intake and drink a full glass every 1–2 hours. If you would rather sip throughout the day, remember to refill your glass or water bottle enough times to meet your total daily intake.
• Use an app or fitness tracker. If you tend to forget to drink water, hydration apps such as Aloe Bud and Aqualert can be programmed to send you a reminder when it's time to drink more.
• Try flavored water. Many people find plain water boring to drink. Opting for still or sparkling flavored water with no sugar added can help make water consumption feel like more of a treat instead of a chore.

A Word From Verywell

Staying hydrated is crucial for health maintenance, but it is just as important to make sure that you are getting the right amount for your individual needs. If you're unsure whether you're not drinking enough or are getting too much water, ask your healthcare team for more guidance.

Keep in mind that in addition to water, many foods also have a high water content that can help provide extra hydration. Remember to follow the 80/20 rule: 80% of your intake should come from water and other beverages while the remainder can be found in the foods you eat. Be sure to choose healthy, whole foods whenever possible—especially fruits and vegetables that contain a lot of water. When you meet your recommended water intake, you may start to notice that you feel better and have more energy.