How Much Water Do I Need in a Day

How Much Water Do I Need in a Day?

Water is the body’s most important nutrient.

You might not think of water as a “nutrient,” but given all its functions in the body, it’s definitely the most important nutrient you can offer your body.

But how much water do you need each day?

Water Facts

  • You can go about 8 weeks without food, but only days without water.
  • Water is found in every single tissue in the body.
  • Our bodies are made up of 70% of water. Water makes up the bulk of all body fluids, including saliva, blood, lymph, intracellular fluid (the fluid within cells), and extracellular fluid (the body of fluid outside cells).
  • Water is often called the “universal solvent” since it can dissolve a wide variety of substances (more than any other liquid in fact).

Water’s Role in the Body

  • Water helps deliver nutrients and oxygen to cells and transports waste away from cells and out of the body through urine, sweat, expiration, and tears.
  • Water helps cushion and lubricate our joints, absorb shocks to the body, and prevent tissues from sticking together.
  • Water moistens, warms + humidifies oxygen for easier breathing.
  • Water helps regulate optimal body temperature.
  • Water helps improve the communications between cells and maintain their electrical properties

Water Consumption + Loss

Our bodies are truly amazing, but when it comes to water, it can only produce a very small amount of its water needs through metabolic processes. Most of our it needs to come from the beverages and foods we consume.

Since our bodies don’t store water long-term (like a camel can) optimal health requires daily consumption of sufficient high quality water.

  • On average our water intake comes from:
    • Ingested liquids – 64%
    • Ingested food – 28%
    • Metabolic – 8%
  • 4 main ways we lose water:
    • Urine – 60%
    • Sweat – 24%
    • Breathing – 12%
    • GI Tract – 4%

Also, water loss is dependent on exercise.

Bio-Individual Needs Affecting Water

Just like with nutrition, water needs are always bio-individual. Some people will need more water than others in hotter temperatures, during intense physical activity, or high stress, fever, blood sugar dysregulation, epsom salt baths, etc.

Water needs will also be dependent on the diuretics you drink. Diuretics are any substance, that promotes diuresis, which causes water loss by increasing urine production. Diuretics are any beverages containing caffeine or sugar, like caffeinated coffee, teas, and soda, fruit juices, alcohol, and even Gatorade, sugary foods, and some medications.

Common Diuretics

Here’s a list of common diuretics that cause you to lose water including, but are not limited to:

  • Caffeinated drinks
    • Coffee
    • Black/green/white tea
    • Soda
    • Energy drinks
    • Kombucha, etc.
  • Sugar containing drinks
    • Fruit juices
    • Soda
    • Sweet tea
    • Sports drinks like Gatorade/Powerade
    • Alcohol
  • Diuretic medications
    • Spironolactone
    • Furosemide
    • Hydrochlorothiazide, etc.

Surprised to see Gatorade on this list? Gatorade has 36 grams of sugar in it,


That amount of sugar is essentially the same as a 12 oz Dr. Pepper.

Check out this video about how high sugar drinks (like Gatorade) can worsen your hydration.

Sigh…I just think of all those years I played sports and thought I was doing my body good by drinking Gatorade. It explains a lot of the delayed recovery from injuries (depleted minerals/water = longer recovery/healing).

Daily Water Formula

As a starting point, to find how much water you need in a day, use this Water Formula.

To calculate your daily water needs, take 1/2 your body weight (lb) in oz + 1.5 x oz of diuretics.

Ex. If you weigh 150 lbs and drink 1 cup of coffee in the morning and 1 cup of juice after lunch, your water intake should look like this:

150 lb = 150 lb/2 = 75 fl oz of water per day

2 cups of diuretics = 2 x 8 fl oz = 16 fl oz diuretics x 1.5 = 24 fl oz that need to be added to daily water intake

75 oz + 24 fl oz = 99 fl oz water or 12.4 cups or 2976 mL per that day

If you drink diuretics, your need will change based on how much you drink.

NOTE: There is not a formula for replacing fluids after eating high sugar foods, but drinking to thirst is a good way to stay hydrated. Too much water, however (more than 1 gallon), can cause it’s own problems. The key is balance and moderation.

Other Factors Affecting Water Needs

It’s definitely worth mentioning that that quality of your water matters just as much as the amount you’re drinking.

Water is meant to carry an electrical charge which is determined by the nutrients, or electrolytes/minerals, in the water.

When water is stripped of these nutrients, water will attempt to regain its charge by pulling electrolytes/minerals from where it can–aka YOUR tissues and cells.

This is why distilled, purified, and acidic waters should be avoided as it can worsen hydration.

According to the EPA, the recommended pH for drinking water is 6.5-8.

Out of 20 bottled waters tested in this project, the average pH was 6.8.

Alkaline waters have become popular, but there’s a big difference between alkaline water and alkalized water.

Alkaline water, like Essensia, have chemicals and minerals added to it in order to increase the alkalinity. Alkaline waters have been reported to cause metabolic problems in the body such as kidney stones and metabolic alkalosis.

Alkalized water (alkaline ionized or reduced/ionized water) is water that is electrolyzed in an ionizer machine. Alkalized waters do have some reported benefit, but could negatively impact digestion by diluting stomach acid (although any fluid can do this if you drink too much around your meals).

Fine Waters has an awesome database of bottled waters including the TDS (total dissolved solvents) and pH.

Consider checking the pH of your water as well as contaminants when evaluating the quality of it.

Signs of Dehydration

So now you have a nifty little formula to find your daily water needs including how to account for diuretics.

Keep in mind that while we try our best to logically configure our needs, we are humans, and we are complex creatures–not math equations.

That’s why knowing the signs of dehydration, both early and mature, are important.

Here’s a chart with the most common early + mature dehydration signs according to the Nutritional Therapy Association.

AnxietyJoint Pain
IrritabilityBack Pain

Water Replacement

When we lose water, we also lose minerals/electrolytes. If we only replace the fluids but not the nutrients that were also lost, you can create a deficiency of minerals.

If you’re needing to replenish your body with water, the best source of nutrients are going to of course come with a variety nutrient-dense foods like vegetables. A high quality electrolyte supplement can also help replace certain minerals lost. Adding electrolytes and even a little sea salt that contains minerals can help the body hang on to fluids better.

Many electrolytes contain sugar, dextrin, or maltodextrin (like the Whole Foods Brand). These can worsen hydration and usually contain other synthetic ingredients that don’t do you any favors.

The cleanest brands of electrolytes I’ve found are:

They are both:

  • Gluten free
  • Dairy free
  • No added sugar
  • No artificial sweeteners
  • Keto/Paleo friendly

Dr. Berg’s is designed more for overall nutritional support. It’s is higher in potassium, which is beneficial especially if you eat refined carbohydrates (which takes water to digest: carbo-hydrate). It also has trace minerals to support minerals not obtained from vegetables due to soil depletion.

LMNT is a lot higher in sodium, making it great performance supplement if you’re sweating a lot.

Price wise, Dr. Berg’s is about $0.74-$0.85/serving based on how many containers you buy, while LMNT’s is $1.10-$1.50/serving.

Read more about how to stay hydrated here.


  • Water is the body’s most important nutrient.
  • Water is needed for many functions in the body.
  • Diuretics cause increased water loss.
  • The Daily Water Formula can help you find how much water you need in a day.
  • Water carries an electrical charge.
  • Water is not meant to be consumed “purified” or distilled (minerals completely removed)
  • The quality + pH of water matters and poor quality/imbalanced pH can negatively affect hydration.
  • Water replacement should include electrolytes (first from vegetables, then from supplemental aids) to promote better hydration + to prevent creating mineral deficiencies.

Based on the Daily Water Formula, have you been getting enough water in a day??

Want to know how to get more water?

Click here for healthy habits to stay hydrated.


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