How much water do you really need to drink each day? Spoiler: It's not 8 glasses.

We all know that humans need water to survive, but how much just plain water do we actually need to consume each day to be healthy?

If your instinct is to say 6 to 8 glasses of water a day, you're not alone. For many of us, that figure has been ingrained into us since we were kids by health class teachers, family doctors and concerned caregivers alike.

However, needing 8 glasses a day of water is a total and complete myth.

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Despite being deeply embedded in our collective conscience, there's little to no scientific evidence to back up the idea that drinking 8 glasses—or any specific number of ounces—of water per day is ideal. This fact might take a minute to digest, since these days so many of us carry water bottles measured in specific ounces to help us stay hydrated and may even track our water consumption with an app or daily planner.

Knowing how many ounces of water we should drink and tracking how much we do drink may give us a satisfying sense of control, but it's largely meaningless. According to the Mayo Clinic , staying hydrated isn't so much about how much water you drink but about how much fluid you consume overall, including from foods and beverages besides water. And that amount is different for every person because every person's body is different.

Additionally, our circumstances are different each day. If you're exercising or sweating from the heat, your body's hydration needs change. If you're sick, pregnant or breastfeeding, your hydration needs change. Certain medications can alter how much fluid your body needs, as can a high-salt diet.

But there must be some kind of guideline, right? We can't just be willy nilly drinking water whenever we feel like it in the age of step counts and sleep tracking apps, can we?

Feeling thirsty? Photo by Andrea Piacquadio/Pexels

Inadequate hydration is linked to early aging and chronic disease , among other things, so it's important to get enough fluids. The U.S. National Academies of Sciences, Engineering, and Medicine lists adequate daily fluid intake as:

- About 15.5 cups (3.7 liters) of fluids a day for men

- About 11.5 cups (2.7 liters) of fluids a day for women

That doesn't mean that's how much water you should drink. Fluids can be found in food —many fruits and vegetables are high in water content and count toward hydration. Any milk you drink and even yogurt or cottage cheese you consume adds to your fluid intake. Soups and broths? Super hydrating. Other beverages, even ones that contain caffeine as long as you don't overdo it, count as well. And again, those numbers are just a general guideline. Your body size, overall health, environment and lifestyle all influence your own specific hydration needs.

Some doctors point out that we have a natural mechanism to tell us when we aren't well-hydrated—thirst. "Drink when you're thirsty" may sound like basic advice, but it's what many physicians recommend. However, thirst is a sign that your body is already mildly dehydrated, so some recommend drinking before you get thirsty as well.

Just don't go too far that way, either. Another common myth is that you can't drink too much water, but that's not true. A tragedy in 2023 in which a healthy mother of two drank four bottles of water in about 20 minutes and died of water intoxication highlighted the importance of not drinking too much water too fast. And drinking an excess of water overall, though rarely a problem for well-nourished adults, can make it hard for your kidneys to process properly .

One way to gauge your hydration level besides monitoring thirst is to check your pee. While it doesn't need to be clear (contrary to popular belief) it shouldn't be dark. According to Healthline 's handy hydration chart , "lemonade" is about the shade you're looking for. Too clear means you're probably overhydrating. Darker than a light beer and it's time to up your liquid intake a bit.

Water is good. Hydration is important. Pay attention to thirst. Shoot for lemonade-shade pee. That ought to keep you on the right track for getting enough liquid without having to keep track of how many glasses or ounces of water you drink each day.