How Much Water Should You Drink in a Day?

  • Evidence based
  • Fact checked
Girl drinking water after a jog in the outdoors

The amount of water you drink per day depends on various factors. There are a lot of benefits of drinking adequate water. Read on to know how much is adequate for you and what factors you should consider.

You must have heard that drinking plenty of water is good for your health. But how is one to figure out how much water should you drink in a day? There are readily available guidelines to give you a broad understanding of the body’s hydration requirements.  But, individual requirements vary from one person to another.

Let us find out what happens if you do not drink adequate water, or conversely if you drink too much water. Below is a table with a simple broad outline of the recommended levels of water intake per day:

How much water should you drink in a day?

According to a report [1]National Academics: Report Sets Dietary Intake Levels for Water, Salt, and Potassium To Maintain Health and Reduce Chronic Disease Risk, the recommended fluid intake is:

MEN 3.7 liters125 ounces

15.5 cups

WOMEN2.7 liters 91 ounces

11.5 cups

The numbers stated above are the minimum recommendations. There are other factors that are also considered to determine your water intake.

Factors affecting your body’s water intake

Maintaining a stable water balance in the body is very important for overall health. But our body’s fluid needs are unique and are determined by several variables. No wonder it is very difficult to formulate one guideline or formula for the ideal level of water consumption. Let us look at the factors that determine the amount of water your body needs.

Diet: If your food is spicy, highly salty, and sugary, your body will need more water. Likewise, if you consume too much coffee, you will lose a lot of body fluids through frequent urination.

Climate: Your body will need more water in summers than in cooler seasons, as you perspire a lot in a hotter environment. If you spend time in the sun, or in a hot room, your body will require more water.

Geography: Your body will need more water on an average per day if you are living in hot, dry, and humid geographies, and high altitudes like mountains.

Physical activity: If your job involves a lot of travel, walking, or standing, you will require more water. Likewise, if you exercise a lot regularly, your body will require more fluids.

Overall health: If you have a fever or infection, or you have lost body fluids due to diarrhea or vomiting, you will require more water. People with conditions like diabetes also need a lot of water.

Breastfeeding or Pregnant Women: When you are pregnant or breastfeeding your baby, you will require extra water as your body has to compensate for the water requirement of your baby too.

Health benefits of water

The human body is made up of 55%-78% water, so staying hydrated is very important. Every part of your body down to the last cell requires a specific amount of hydration to stay healthy and function normally.  The below table lists the percentage of water content in the different organs of the body:


By now we know how much water to drink per day according to our individual conditions and requirements. We also know how much water individual parts of our body require on average. Let us see now see what the benefits of drinking water are:

Improves Digestion: Having enough water helps your body in producing enough gastric acid to dissolve fiber and fats. This helps in regulating bowel movements and prevents constipation. Water helps in lessening the burden on the liver and kidneys by making it easier to flush out toxins with lesser effort. Moreover, water also prevents the formation of kidney stones.

Muscle and Joint Health: Water is a life-sustaining compound. It is necessary for survival. Water promotes the growth of your muscles. It lubricates your joints, thus preventing joint pains and muscle cramps. Having adequate water helps in improved physical performance as you will be able to work longer and harder.

Boosts Metabolism: Studies show that people who have adequate water have a better metabolic rate than those who drink less water. The metabolic rate increases with an increase in water intake. It also means that your body has the ability to burn extra fat and calories. This is a sign that your body is fit. 

Helps in expelling body waste: Drinking enough water helps your body to send out waste through defecation, urination, and perspiration. Drinking an adequate amount of water helps in preventing constipation. A study [2]National Kidney Foundation: 6 Tips To Be “Water Wise” for Healthy Kidneys finds that water helps your kidneys to expel waste from the blood and keep the blood vessels clean. In addition, an organizational recommendation [3]Centers for Disease Control and Prevention: Water and Healthier Drinks states that taking more fluids helps in keeping conditions like urinary tract stones and bladder infections at bay.

Prevents Dehydration: According to the Centers for Disease Control and Prevention, your body loses fluids through sweating, when you work out, have a fever, or experience vomiting or diarrhea. Your body’s natural hydration levels can be restored only by taking fluids like water.

Helps in optimal brain function: Your hydration levels have a strong impact on your brain. According to a study, loss of body fluids after exercise can impair concentration levels and mood in women. Additionally, the frequency of headaches was also high.

Another research [4]Cambridge University Press: Mild dehydration impairs cognitive performance and mood of men says that loss of fluids affects memory in men. It also increased fatigue and feelings of anxiety. According to a study [5]PubMed: Effects of drinking supplementary water at school on cognitive performance in children, dehydration can lead to impaired memory, slower brain performance, and irritable mood in older adults and children.

What is dehydration?

When your body loses more fluids than it consumes, it is called dehydration. It is the absence of sufficient levels of water in the body for its normal functioning. This can be a result of the loss of as little as 1.5% of the body’s water levels. 

Thirst is the most basic sign of depletion in the body’s water levels. Apart from that, the human body shows several other dehydration signs and symptoms that range from mild to fatal. Let’s take a look at some of them.

Signs of dehydration

The symptoms or signs of dehydration depend on its severity. Your body will show certain symptoms before complete dehydration takes place. Severe dehydration means you need medical aid. If you show any of the symptoms of severe dehydration, seek medical help immediately

Symptoms of Mild to Moderate Dehydration

Symptoms of Severe Dehydration

Increased thirst

No sweat production

Decreased urination

Rapid breathing

Dry mouth

Low blood pressure

Less tear production

Fever and Chills

Excessive thirst




Rapid heart rate


Wrinkled skin

Dry skin

Sunken eyes


No urine or Dark urine

Dehydration in children

The bodies of children and infants contain more water than adults. This makes them more prone to dehydration. As their kidneys are not fully mature, they tend to lose more water. Additionally, infants usually have difficulty in communicating their want for water.

Infants are also at high risk of vomiting, fever, and diarrhea, which are all the causes of dehydration. Illness in infants makes it more difficult for them to retain body fluids. The American Academy of Pediatrics recommends ORS solutions for treating dehydration in kids and infants. These solutions are available in every drug store. You can also prepare ORS [6]Rehydration Project: Oral Rehydration Solutions: Made at Home solutions at home.

Home Made ORS Solution

  • Take 1 liter of clean drinking water and boil it.
  • Then cool the water and add 6 teaspoons of sugar to it.
  • Then add ½ teaspoon of salt and mix till the sugar and salt have dissolved.

Dehydration in older adults

Just like kids and infants, older adults are also at high risk of dehydration. The use of certain medications might lead to severe dehydration in them. Many of them have a weak sense of thirst, or might physically not be able to get water.

Common signs of dehydration in the elderly are confusion, blood pressure, constipation, and dizziness. Urinary tract infection is another cause of dehydration in older adults. If the condition becomes serious, take the person to a doctor.

Winter dehydration

As we do not sweat much during cold winters, many of us believe that we don’t lose much water from our bodies. But this is a misconception. Have you  noticed your breath form short puffs of white smoke when you exhale in winters? This is the water that your body is losing. This loss of water from your body should be replaced by drinking adequate water to prevent dehydration. 

Unfortunately, your body’s thirst response is also reduced in cold temperatures. Therefore, you consume less water. This means that not only does the cold climate make us lose water from our bodies, it also tricks us into consuming less and less water. So one needs to be extra cautious of drinking water and healthy fluids in cold climates.

Tips for staying hydrated

Your best solution against dehydration is to prevent it before it sets in. Given below are 5 tips on staying hydrated.

  • Your thirst is a sign that you are already dehydrated. Don’t wait till your body is thirsty. Drink lots of fluids or sip water throughout the day, especially when the weather is hot or if you exercise daily.
  • If drinking plain water is boring, you can add flavor. Add a spoonful of lemon or orange juice to your bottle of water. You can also try ice pops, broths, or sports drinks. Remember to stay away from alcohol and caffeine.
  • Some vegetables and fruits are rich in water content. You can try eating fruits like strawberries, watermelon, pineapples, cantaloupe, and peaches. Vegetables like radish, cucumber, tomatoes, zucchini, leafy greens, and celery also have high water content.
  • Staying indoors is another best solution to dehydration caused by excessive sun exposure. If you have any outdoor activities, it is better to time them during the early mornings or in the evenings.
  • Wearing light-colored, loose-fit clothes allows your skin to breathe. You can wear a wide-brimmed hat when you go out in the hot sun to keep your head cool. Use a good sunblock to protect your skin.

What happens if you drink too much water?

Rarely ever does one come across health problems caused by an excess of water. The body normally finds it far easier to deal with the excess of water than with  the lack of it.  Having said that, there are scenarios where drinking too much water can prove dangerous for health.

Water intoxication, water poisoning, and hyponatremia are just some of the examples of health issues caused by the over-consumption of water. Drinking too much water can cause disruptions in brain health as well, leading to brain swells. Some of the symptoms of excess water consumption are: 


  • Headache
  • Seizures
  • Fatigue
  • Brain Swelling
  • Lethargy
  • Vomiting
  • Confusion
  • Lung congestion
  • Coma

Hyponatremia is a condition when the sodium level of your blood becomes too low. Though rare, this condition can lead to death. People with diabetes and endurance athletes are at high-risk.

Take Away

Water is beneficial to every part of your body. It is good to follow body signals when it comes to drinking water. There is no need to count the number of glasses of water you are drinking per day. It is rarely ever possible to consume too much water to the point of making it unhealthy or fatal.

Though there are many sources of water like the food you eat or other beverages you drink, plain water is the healthiest form of consuming water. If you have a medical condition and you feel that the water you are drinking isn’t enough for your body, consult your healthcare provider and seek medical advice.

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