How Much Water Should You Drink Each Day?

Water is essential to good health. About 50% to 60% of your body is water, and keeping that level in balance through hydration is important. There is actually no universal recommendation for how much water you should drink each day. Instead, there are recommendations for daily fluid intake, which can come from water, other beverages, and food.

Some health experts use the general recommendation of 11.5 cups of fluid per day for women and 15.5 cups of fluid per day for men. Because food typically gives you about 20% of your daily water needs, about 80% of the day's fluids will have to come from beverages, such as plain water. That means, each day, women would need to drink about nine cups of fluid and men would need to drink about 13 cups of fluid.

The amount of fluid you need to drink each day can vary person to person, day to day. This is because the amount of fluids you lose through sweat, urination, feces, and respiration can change. Factors like activity level, weather, and health status can all affect the amount of fluid you lose and need.

A group you likely don't need to give any water to is infants younger than 6 months. If they are getting the recommended amount of human milk or infant formula, that alone is probably enough fluid. When you start to give babies food, you can begin giving them small amounts of water, up to four to eight ounces a day. You can up your baby's water intake after they are a year old. 

Benefits of Drinking Water

Your body depends on water to function. Water helps with:

  • Body temperature regulation
  • Joint lubrication and cushioning
  • Tissue protection
  • Waste removal through urination, sweat, and bowel movements

Besides needing it for daily function, there are a number of other benefits to drinking water.

May Promote Healthy Aging

Adults who drink plenty of fluids like water appear to have several better health outcomes than those who do not drink enough fluids. Researchers came to this conclusion after gathering health data from more than 11,000 adults over a 30-year period. The researchers looked at people's serum sodium levels, which can indicate how much water a person drinks—the higher the levels, the less fluid people have taken in.

People with higher serum sodium levels—meaning those who were not as well-hydrated—had advanced biological aging and more chronic conditions like heart and lung disease. They also died younger.

More research is needed to solidify the connection between poor hydration and accelerated aging.

May Reduce Risk of Type 2 Diabetes

Choosing water—or other unsweetened beverages—over sugary drinks can help prevent type 2 diabetes. The risk reduction isn't so clear if water is already your drink of choice. Rather, the risk reduction happens when you replace sugar-sweetened beverages or fruit drinks with water.

Helps Manage Weight

Staying within the ideal weight range your healthcare provider sets with you can help in managing or preventing certain conditions. Drinking water can help you reach or stay in that weight range. First, water is zero calories. Second, drinking water supports fat loss through increased fat burning. Conversely, consistent underhydration has been linked to increased body weight.

Research has also shown that children who drink water rather than sugary drinks are less likely to be overweight.

Prevents Constipation

When you are constipated, bowel movement can be difficult or painful. The bowel movements might also happen fewer than three times a week. The stool can be hard, dry, or lumpy. Sometimes conditions or medications can cause constipation. Oftentimes your diet is causing your constipation.

One of the most common causes of constipation is a lack of water or fluid intake. When you are not properly hydrated, stool moves through your digestive system more slowly. Once you start taking in more water or other fluids, your constipation will likely improve. Staying well-hydrated can help prevent constipation in the first place.

Fosters Memory and Cognition

Water makes up 75% of your brain mass. Not adequately replenishing the water you lose can have cognitive effects. Losing just 2% of your body's water supply can cause short-term memory loss and interfere with anything that requires psychological and physical tracking.

Research also shows that children who stay hydrated throughout the school day have an increase in their ability to focus.

Promotes Skin Hydration

If you have dry or rough skin, you may want to consider drinking more water. There is some evidence that staying hydrated can not only reduce dryness, but also prevent premature aging. Likewise, keeping your skin hydrated may create the barrier your skin needs to prevent dryness and roughness.

Optimizes Exercise Capabilities

When exercising, the most important thing you can do to improve your performance is to make sure you are drinking enough water before you work out and replenishing lost fluids afterward. In fact, research indicates that drinking enough water can help you work out longer and at a higher intensity. Meanwhile, dehydration can detract from your performance—even when your loss is just 2% of your body’s water stores.

May Help Prevent Heart Failure

Drinking enough water each day may reduce the risk of severe heart problems. Researchers of one 2022 study found that staying well-hydrated throughout your life may slow the decline of cardiac function. Staying hydrated may also reduce your risk of heart failure.

When Should You Drink More Water?

There are times when you may need to increase your usual water intake. Here are some factors that could impact how much water you need to drink in order to stay optimally hydrated:

  • Illness: When you're sick, staying hydrated is an important part of the recovery process. You can lose more fluid than normal if you sweat from a fever, have a runny nose, or experience vomiting or diarrhea. Drinking water prevents you from getting dehydrated.
  • Hot weather: Whether you are working in the heat or simply spending the day in the sun, high temperatures can lead to dehydration and heat illness if you do not drink enough water. If you are working outside, drink before you get thirsty. Drink 8 ounces of water every 15 to 20 minutes.
  • Higher elevations: Whether you regularly hike at high altitudes or you live at a higher elevation, you will tend to lose more fluid due to respiration. The higher your elevation, the greater potential for fluid loss. Make sure you are prepared for this water loss—especially if it's your first time at a higher elevation.
  • Frequent exercise: If you are an athlete or a frequent exerciser, you need more water than someone who is less active. Of course, your exact needs will vary depending on the type of exercising you are doing. The key, though, is to drink water before, during, and after working out.
  • Breastfeeding: If you are breastfeeding or pumping, you will need more water than normal—as much as 16 cups of water a day—which can come from food and beverages. One way to ensure you are getting enough water is to drink a full glass each time you nurse or pump.
  • Pregnancy: When you are pregnant, you may need to drink as much as 96 ounces of water a day. Not only will this extra water aid in digestion, but it will also help form the amniotic fluid around your baby.

Signs You Are Not Drinking Enough Water

When you do not drink enough water or you lose more water than you take in, you can become dehydrated. In severe cases, dehydration can become life-threatening causing complications like increased heart rate (tachycardia) or low blood pressure. Even mild cases of dehydration can cause uncomfortable symptoms. Here are some signs that you or your child may not be drinking enough water.

Symptoms of Dehydration in Adults

In adults, symptoms of dehydration can include:

  • Feeling very thirsty
  • Having a dry mouth
  • Urinating and sweating less than usual
  • Having dark-colored urine
  • Experiencing dry skin
  • Being tired
  • Feeling dizzy

Editor's Note: As you get older, your sensation of thirst declines. Because of this, older adults might not be physically cued with thirst that they need to drink water and so often wind up drinking less than they need.

Symptoms of Dehydration in Children

If an infant or young child is dehydrated, it is important that they be brought to a healthcare provider, especially if their symptoms include:

  • Having a dry mouth and tongue
  • Crying without tears
  • Having no wet diapers for three hours or more
  • Having a high fever
  • Being unusually sleepy or drowsy
  • Experiencing irritability
  • Having eyes that look sunken

Editor's Note: Sometimes dehydration can be life-threatening. For this reason, it is important to get immediate medical attention if you experience any of these symptoms:

  • Confusion
  • Fainting
  • Lack of urination
  • Rapid heartbeat
  • Rapid breathing

Can You Drink Too Much Water?

While staying hydrated is important, it is possible to drink too much water. Usually if you overhydrate, your kidneys can handle it. But sometimes if you drink a lot of water—particularly if you have a condition that affects your ability to filter out water or that makes your body retain water—the overhydration can lead to dangerous consequences.

Athletes, those who drink an excess amount of water as part of a competition, and those who are persistently thirsty despite having no physical condition causing the thirst (psychogenic polydipsia) are more likely to overhydrate. Psychogenic polydipsia is most common among people with certain conditions, including schizophrenia, bipolar disorder, chronic alcoholism, autism, and dementia.

The excessive water intake can cause you to have too much water and not enough sodium in your body. These low sodium levels in the blood is known as hyponatremia, which can be dangerous. While it's possible to have no symptoms or mild symptoms like lethargy, severe overhydration may cause confusion or seizures. 

Getting to a point where you experience negative effects from drinking water is rare. For instance, a young adult with normal kidney function would need to regularly drink 6 gallons of water a day to exceed the body’s ability to rid water.

A Quick Review

Drinking water every day is essential to your overall health. For this reason, it is important to get proper fluid intake, which can come from a mix of water, other beverages, and food. That means that you might need roughly nine cups of water each day if you are a woman and 13 cups if you are a man. Of course, the exact amount of water you need will vary depending on factors like how active you are, where you live, and what medical conditions you have.

Making sure you are consistently drinking enough water can benefit you in a number of ways. Aside from keeping your body and skin hydrated, drinking the right amount of water can also help prevent heart disease and promote healthy aging. Just make sure you stay within typical recommendations. Drinking too much or too little water can come with serious consequences.

If you are not sure how much water you should be drinking, talk to a healthcare provider. They will evaluate your medical history, current health, lifestyle factors, and environmental factors to determine what amount is right for you.

Was this page helpful?
26 Sources 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.
  1. Ohashi Y, Sakai K, Hase H, Joki N. Dry weight targeting: The art and science of conventional hemodialysisSemin Dial. 2018;31(6):551-556. doi:10.1111/sdi.12721

  2. Centers for Disease Control and Prevention. Water and healthier drinks.

  3. Academy of Nutrition and Dietetics. How much water do I need?

  4. Yamada Y, Zhang X, Henderson MET, et al. Variation in human water turnover associated with environmental and lifestyle factors. Science. 2022;378(6622):909-915. doi:10.1126/science.abm8668

  5. U.S. Department of Agriculture. Dietary guidelines for Americans 2020-2025.

  6. Dmitrieva NI, Liu D, Wu CO, Boehm M. Middle age serum sodium levels in the upper part of normal range and risk of heart failureEur H J. 2022;43(35):3335-3348. doi:10.1093/eurheartj/ehac138

  7. Dmitrieva NI, Gagarin A, Liu D, Wu CO, Boehm M. Middle-age high normal serum sodium as a risk factor for accelerated biological aging, chronic diseases, and premature mortalityeBioMedicine. 2023;87:104404. doi:10.1016/j.ebiom.2022.104404

  8. Centers for Disease Control and Prevention. On your way to preventing type 2 diabetes.

  9. Pan A, Malik VS, Schulze MB, Manson JE, Willett WC, Hu FB. Plain-water intake and risk of type 2 diabetes in young and middle-aged women. Am J Clin Nutr. 2012;95(6):1454–1460. doi:10.3945/ajcn.111.032698

  10. Thornton SN. Increased hydration can be associated with weight lossFront Nutr. 2016;3. doi:10.3389%2Ffnut.2016.00018

  11. Moreno MA. New information about the benefits of drinking water compared with sugar-sweetened beverages. JAMA Pediatr. 2016;170(3):304. doi:10.1001/jamapediatrics.2015.2512

  12. Centers for Disease Control and Prevention. Symptoms & causes of constipation.

  13. Forootan M, Bagheri N, Darvishi M. Chronic constipation: A review of literatureMedicine. 2018;97(20):e10631. doi: 10.1097/MD.0000000000010631

  14. Zhang J, Zhang N, Du S, et al. The effects of hydration status on cognitive performances among young adults in Hebei, China: A randomized controlled trial (RCT). Int J Environ Res Public Health. 2018;15(7):1477. doi:10.3390/ijerph15071477

  15. Backes TP, Fitzgerald K. Fluid consumption, exercise, and cognitive performanceBiol Sport. 2016;33(3):291-296. doi:10.5604/20831862.1208485

  16. Akdeniz M, Tomova-Simitchieva T, Dobos G, Blume-Peytavi U, Kottner J. Does dietary fluid intake affect skin hydration in healthy humans? A systematic literature reviewSkin Res Technol. 2018 Aug;24(3):459-465. doi:10.1111/srt.12454

  17. Kerksick CM, Wilborn CD, Roberts MD, et al. ISSN exercise & sports nutrition review update: Research & recommendationsJournal of the International Society of Sports Nutrition. 2018;15(1):38. doi:10.1186/s12970-018-0242-y

  18. Centers for Disease Control and Prevention. Heat stress.

  19. Ladd E, Shea KM, Bagley P, et al. Hydration status as a predictor of high-altitude mountaineering performanceCureus. 2016;8(12):e918. doi:10.7759/cureus.918

  20. Academy of Nutrition and Dietetics. Nursing your baby: What you eat and drink matters.

  21. American College of Obstetricians and Gynecologists. How much water should I drink during pregnancy?

  22. Lacey J, Corbett J, Forni L, et al. A multidisciplinary consensus on dehydration: Definitions, diagnostic methods, and clinical implicationsAnn Med. 2019;51(3-4):232-251. doi:10.1080/07853890.2019.1628352

  23. MedlinePlus. Dehydration.

  24. Merck Manuals Consumer Version. Overhydration.

  25. Peechakara BV, Gupta M. Water toxicity. In: StatPearls. StatPearls Publishing; 2022.

  26. Krogulska A, Nowicka D, Nowicki Z, Parzęcka M, Sakson-Słomińska A, Kuczyńska R. A loss of consciousness in a teenage girl with anorexia nervosa, due to polydipsia: Case report and a mini review. Eat Weight Disord. 2019;24(5):969-974. doi:10.1007/s40519-018-00636-x

Related Articles