Dr. Erin Hendriks

How much water should you really drink in a day?

Eight glasses of water per day may be enough for you. But you may need more (or even less).


July 18, 2022

Written by:

Medically Reviewed by:

Dr. Erin Hendriks

Board-Certified Physician


November 20, 2023


Easy, right? Haven’t we all been told to drink our eight 8-ounce glasses of water a day, a good solid 64 ounces? And that advice isn’t wrong. It’s just that, as with many things related to your health, things can get a little more complicated, especially with irritable bowel syndrome (IBS). 

How much water you should drink depends on your urine color

Eight glasses of water per day may be enough for you. But you may need more (or even less). We’ll cut to the chase: it mostly comes down to urine color. You’re aiming for light-colored urine that falls into the range between straw-colored and pale amber. 

Colorless urine can mean you might be getting rid of too many electrolytes and may want to drink a little less. Dark yellow or brownish urine means you may want to help your body filter toxins by drinking a little more water. 

How to know you’re drinking enough water

Some of us can’t be detached from our mega-sized water bottles, while others of us drink so little, we’re practically desert tortoises. If your urine is pale yellow and you’re not usually thirsty, however, you’re probably drinking about the right amount of water for you personally. Some variety between people when it comes to their fluid needs is normal. It’s also fine to experiment a little with how much water you drink in a day. 

As a starting point, if you live in a temperate place, the National Academies of Sciences, Engineering, and Medicine says:

  • Women should drink about 11.5 cups (2.7 Liters) of water a day
  • Men should drink about 15.5 cups (3.7 Liters)  of water a day

Like we said, that’s only a starting point. Certain things can affect how much water you should be getting: 

  • If you’re in humid or hot weather, try to drink more water to make up for sweating
  • When you’re exercising or doing a lot of physical activity, be especially careful to stay hydrated 
  • If you notice that you’re frequently tired, feel mentally foggy, or feel irritable or more anxious than usual, try adding in at least another glass of water a day
  • If you’ve been vomiting or have diarrhea, you need to make up for the fluid loss 
  • If you’re sick or if you’re on certain medications, you may need more water (Note: some NSAIDs, opiates, and other medications encourage water retention, in which case you may need less water)
  • If you’re breast-feeding or pregnant, drinking water is very important

Also, the biggest factor of all: if you’re thirsty, drink more water! Thirst is a powerful indicator, and could be an early sign that you’re already getting dehydrated.

How IBS affects the amount of water you should drink

IBS can be related to hydration in a few different ways. If your IBS symptoms include constipation, a little more water may help with that. 

If, on the other hand, you have to deal with diarrhea, the answer could also be more water. That’s because diarrhea can contribute to dehydration and can deprive you of electrolytes. For each bout of diarrhea, drink another cup of water or other liquid. Broth could be a good choice, since it contains salt. A sports drink or even a banana could both add moisture and electrolytes to help you stay balanced. 

Why drinking enough water matters 

Drinking plenty of water isn’t just a trend or a reason for celebrities to show off fancy water bottles. Your body weight is 50 to 70% water. Not only are you practically made of water, you also need fluid intake for everyday functions like digestion, sweating, maintaining your blood pressure, joint lubrication, filtering waste, preventing kidney stones, keeping your body temperature stable, making cellular repairs, nerve signaling, promoting healthy skin, and so much more. 

While it’s possible to drink too much water (which is called hyponatremia and can be deadly), suffering from too much water consumption is rare, and mostly something athletes in grueling competitions are concerned about. People with certain medical conditions such as heart or kidney problems may need to be careful with their water intake. 

It’s more common to get too little water, leading to dehydration. Even a 1% water loss can make you feel weaker, more sluggish, more irritable, or as though you’re having trouble focusing. That’s why, when you notice clumsiness, “hanger,” soreness, strong emotions, a headache, exhaustion, or wandering attention, it’s not a bad idea to drink at least half a glass of water.

You don’t have to get your water just from the sink

Eight or more cups a day sounds like a lot of water to some of us. Good thing we can count fruits and vegetables, many of which contain high percentages of water, among our daily quota. In fact, many of us get about 20% of our needed daily water from our food rather than by drinking it directly. 

If drinking enough plain water is a challenge, you can sneak in more water by eating watermelon, celery, spinach, and other water-heavy foods. Juice, coffee, and other beverages help you get enough water, too, though juice can be high in sugar content so you may want to dilute it with extra water or seltzer. 

How Salvo Health can help

At Salvo Health, our digital healthcare platform and virtual clinic provides you with continuous text-based support and care for your chronic condition. Imagine being able to text a certified physician or health coach to avoid flare-ups or manage your pain. Alongside text-based communication, members receive a customized care plan that can take account of how their symptoms can be managed. 

Get immediate access to a coordinated Salvo Health care team, including a certified specialist and board-certified health coach when you join Salvo Health today. 

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