How Long Can Humans Survive With No Water?

by Jay | Updated on July 26th, 2022

The fact that humans need a significant amount of water to survive is no new news. Dehydration can be deadly if extreme and can take place rather quickly: from thirst to organ failure to death. But the question is, how long can humans survive with no water? Hop in, and let’s scroll through this article to find out!

Duration of survival without water

desert dune with blue sky

Water is an essential substance needed by our body to perform vital functions. As simple as keeping our cells alive requires a good amount of water. While answering the question requires consideration of several factors, a person can generally survive for around 3 days without water. But as I’ve said, there are factors to consider, such as:

person on dessert
  • Age
  • Lifestyle
  • Activity level
  • Overall health
  • Gender
  • Height
  • Weight

What an individual consumes also affects the amount of water they need to drink. Someone who consumes food rich in water, such as juices, fruits, or vegetables, won’t need as much water as someone who has been consuming bread, grains, and other dry foods.

Additionally, the environment matters too! For example, too much sweat results in water loss, so they need more water intake. 

Effects of not enough water

Humans cannot last long without a water supply because our body needs water for most vital processes such as:

  • Body temperature regulation through sweat and breathing
  • Digestion by forming saliva and breaking down food
  • Balancing the pH level of the body
  • Moistening of mucous membranes
  • Joint and spinal cord lubrication
  • Body’s utilization of hormones
  • Waste elimination through breath and urine
  • Transportation of toxins out of the cells
  • Oxygen delivery throughout the body

These are the very reasons why dehydration can lead to organ failure. Without water, the body cannot produce sweat; without sweat, there will be a dangerous elevation of body temperature. This may lead to blood volume drop, causing decreased body circulation. These events may lead to a severe drop in blood pressure and, ultimately, death.

Another series of events that can take place is that without water, the body cannot remove toxins from cells and excrete them through breath and urine. The buildup of the toxins can negatively affect the kidneys’ functioning, which may lead to dangerous kidney failure.

Food and dehydration

Fruits and vegetables are water-rich foods that can help prevent or overcome dehydration. Conversely, avoid dry foods such as bread, salty chips, and other dry snacks if suffering from this problem, as they can worsen dehydration. In addition, alcohol and caffeine may also promote dehydration because of their capability to cause excessive urination.

Natural Water Loss

Food and water are necessary for human survival. A human can survive far longer without food than without water. Why? This is because water makes up a large portion of our bodies. Every day, we lose a lot of water.

Humans lose approximately two to three liters of water daily through bowel movements, urine, normal breathing, sweat, and household activity. The amount of water you require each day is determined by various factors.

Age, body fat, gender, health, and geographic region influence this.

Women require between 2 to 2.7 liters of water per day, while men require between 2.5 and 3.7 liters.

When we don’t drink enough water and lose it regularly, our bodies go into war mode.

Risks from dehydration

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According to the Nutrients journal, thirst is the first sign that signals a person that they do not have sufficient water in the body.

Along with this, dry mouth can also occur. Water accounts for 60% of a person’s body weight, and a 3% water loss will already jumpstart dehydration. The brain sends signals for water conservation if water is not readily available. An example is by decreasing the function of the kidneys to decrease urination.

Signs and symptoms of dehydration are:

  • Headache
  • Lack of energy
  • Dizziness and confusion
  • Heat cramps
  • Heat stroke
  • Stiff joints
  • Raised or unregulated body temperature
  • Brain swelling
  • Seizures
  • Sharp changes in blood pressure
  • Shock 
  • Unresponsiveness

These are the reasons why you should consume water regularly! Without water, so many of our bodily functions become chaotic.

Last words

By now, you should already know how important staying hydrated is. Generally, one may not survive for 3 days without water. So make it a habit to drink water regularly and consume foods. Happy hydration!


Self assessed Germaphobe, specializing in everything water, water filters, health and nutrition. Diagnosed with Type 2 Diabetes, I've acquired immense amount of knowledge when it comes to natural, biology, and everything about human anatomy.