Water: How Much is Enough?

Do you know how much water you should drink each day? Most people have heard the “8 x 8” rule; drink 8 glasses of water (8 ounces per glass) every day. Or maybe you’ve heard that you should drink half your weight in ounces each day... But guess what! Both of these are completely and entirely random and not backed up by science in any way. So how much water should you be drinking each day? Well, now things get a little complicated…  

In healthy adults, water constitutes approximately half or more of one’s body weight (this might be where the “drink half your weight in water a day” line originated). Since water takes up more space in our muscles than it does in our fat cells, typically women have about 50% of their body weight as water, whereas men have around 60%, as they are typically more muscular in body composition. Factors that affect how much water someone needs include:

Factors such as activity level affect how much water one actually needs to consume. 

Factors such as activity level affect how much water one actually needs to consume. 

  • body size and composition

  • alcohol consumption

  • environmental temperature and humidity

  • protein, salt and sugar intake

  • medications

  • pregnancy

  • age and medical conditions

  • changes in activity level

A flat rate recommendation of 8 cups of water a day cannot be a universal accurate recommendation, but there actually isn’t a ton of research on this subject. However, the USDA generated Recommended Dietary Allowances (RDA) for the average adult ranges from 2.7 – 3.7 Liters of water each day, equal to about 91 – 125 ounces. That is a lot of water! You can meet much of this water requirement from food sources, but that depends on diet choices, especially if you’re eating enough vegetables, and other hydrating foods. Additionally, I doubt your average woman would say she weighs 182 lbs. (91 x 2, the drink half your weight in ounces of water each day is therefore not completely correct either).

Water Tips

Listen to Your Body

The body attempts to control water consumption via the thirst mechanism, which is triggered when you need to rehydrate. When activity levels are low to moderate, a healthy individual can typically rely on the sensation of thirst to know when and how much water one needs. Explore drinking water at regular intervals in your day and notice how you feel.

Eat Hydrating Foods

Lots of vegetables contain water and can help you hydrate while getting valuable vitamins and phytonutrients. Soup, tea, and even cooked whole grains can be sources of water in your diet. Avoid relying on sugary drinks as thirst quenchers, as these add useless calories and typically a lot of processed chemicals.

Drink Up to Lose Weight

Studies of individuals dieting for the purposes of weight loss who included increased water consumption as part of their program showed improved weight loss results compared to those on a solely on a weight loss program. However this only worked with people on a healthy diet designed for weight loss, so still plan on skipping the meatball sub and opt for veggies and lean protein.   

Pee Peek

Some foods (like beets) can affect urine color, but typically urine should be clear, and light yellow in color. Checking your urine can be a good clue as to if you’ve had enough water. When urine is dark and more concentrated in color, you might want to increase your water consumption.

Spruce Things Up

Try adding unsweetened cranberry, pomegranate, or tart cherry juice to your water to create a wonderful variety of flavors to encourage you to avoid reaching for diet sodas or sugary drinks when thirst strikes. All it takes is just a splash in glass or bottle of water! You can usually find these unsweetened juices in glass bottles at the grocery store.

Hope this was helpful! A reminder that my Group Health and Nutrition Program for Actors is enrolling now; get your spot today here


  • Marieb, E. (2012). Essentials of human anatomy and physiology (10th ed). Benjamin Cummings: San Francisco.

  • Sienkiewicz Sizer, F., Whitney, E. (2014). Nutrition Concepts & Controversies (13th ed). Wadsworth, Cengage Learning: Belmot, CA.

  • Millard-Stafford, M,, Wendland, D.M., O'Dea, N.K., Norman, T.L.,(2012) Thirst and hydration status in everyday life. Nutr Rev., Nov(70) Suppl 2:S147-51. doi: 10.1111/j.1753-4887.2012.00527.x.

  • Muckelbauer, R., Sarganas, G., Grüneis, A., Müller-Nordhorn, J., (2013) Association between water consumption and body weight outcomes: a systematic review. Am J Clin Nutr. Aug;98(2):282-99. doi: 10.3945/ajcn.112.055061.