How Much Water Should You Drink A Day? Tips To Stay Hydrated [UK] 2023

Elesa Zehndorfer

Updated on - Written by
Medically reviewed by Kathy Shattler, MS, RDN

how much water should you drink a day

Did you know that your brain and heart are composed of 73% water? In fact, according to the US Environmental Protection Agency,[1] around 60% of our entire body is made up of water. And that’s exactly why this most powerful hydrogen and oxygen-based essential nutrient remains so valuable to our health! In truth, though, it can be hard to work out exactly how much we should be drinking, let alone whether we should be opting for bottled, tap, sparkling or electrolyte-laced versions. That’s why we’ll be giving you the lowdown of exactly what you need to know in this article – including why it’s so important that you focus on your individual and unique needs.

The simple truth is that without water or H₂O, we could never regulate our body temperature or execute virtually any vital physiological processes.[2] We’d lack a vital protective element for our joints, organs, and tissue, and we would not be able to transport nutrients and oxygen to our cells or dispose of waste from our bodies. In fact, without it, we wouldn’t live longer than a week! 

So read on to find out exactly how to stay hydrated in a way that works for your lifestyle, and find out more about how you can enjoy sparkling water, fruit-infused water, sports drinks, or your refreshing beverage of choice to healthfully meet your water quotient. We’ll even tell you how altering the temperature of your drinks can help speed up fat loss and why H₂0 can make you feel happier and less anxious!

How Much Water Should You Drink In A Day?

According to the National Academy of Medicine,[3] you should aim to imbibe around 13 cups of water a day if you are male and around 9 cups if you are female. 

However, water intake requirements do tend to differ majorly between individuals. If you are exercising in a hot or humid climate, for example, or you are running a fever or experiencing vomiting or diarrhea, you’ll need to increase fluid intake.  If you’re pregnant, the American College of Obstetricians and Gynecologists[4] recommends drinking 8 – 12 cups of water a day (that’s 64 to 96 ounces) to aid digestion and the circulation of nutrients, to help form amniotic fluid around the fetus and to flush waste from the body. 

Benefits Of Water

The benefits of water are profound – and here’s one amazing fact that you might not know – water can affect how happy you feel! And here’s why. 

A recent University of California study[5] reported that when subjects increased their water intake, they felt happier! Conversely, subjects who lowered their water intake reported feeling emotionally lower (less happy), alongside feeling less calm and less content. Similarly, a 2018 article[6] published in the World Journal of Psychiatry reported a clear link between drinking more water and a lower incidence of depression, while Deakin University reported a link between adequate hydration and lowered anxiety levels.[7] 

H₂0 also seems to play a significant role in mediating the onset or emergence of diabetes. Diabetes researchers recommended, for example, in a 2021 academic review,[8] that increasing water intake could prevent or delay the onset of hyperglycemia and subsequent diabetes and that consuming more than 1 liter of water a day reduced the risk of new-onset hyperglycemia by 28%. The American Diabetes Association[9] also notes that drinking enough water prevents dehydration (dehydration can increase the risk of hyperglycemia and diabetes by causing a hormone called vasopressin to rise). 

And here’s an exciting fact – water can even help you lose weight! But how much water would you need to drink to stimulate fat loss and give your diet a boost? It’s a fair question – but before we let you in on that little secret, you also need to know that the temperature of the water that you drink seems vital to play a decisive role in losing weight. In fact, drinking around 0.5 liters of warm water or even hot water has been shown to increase basal metabolic rate or your BMR, thereby promoting thermogenesis (fat burning) by around 30%![10] 

Other physical benefits include[11] better sleep quality, more effective cognition, a heightened mood, and more energy.

What Happens If You Drink Too Little Water?

Unfortunately, if we don’t manage to drink enough water, the side effects of even mild dehydration can appear pretty rapidly, affecting our mental and cognitive, as well as physical state. For example, a loss of just over 2% of the water[12] from our bodies can cause a marked reduction in brain performance! That means compromised performance at work or school, which can be disastrous for exams or that big presentation that you’ve been prepping for. 

Dehydration can also cause bad skin,[13] alongside a raft of serious health complications,[14] including heatstroke, kidney, and urinary tract problems, renal failure, seizures (due to a low electrolyte balance), worsened pain associated with dysmenorrhea[15] (period pain), and hypovolemic shock (a potentially life-threatening condition related to low blood pressure and oxygen levels).

In babies,[16] regular signs of dehydration include drowsiness and crankiness, few or no wet diapers, few or no tears when crying, a fast heart rate, sunken eyes, and a  sunken fontanelle (the soft spot on the top of your baby’s head) – whilst inadequate water intake can also disrupt a mothers’ milk supply[17] which can seriously hinder breastfeeding.  

Even caffeinated drinks can increase your fluid needs[18] since caffeine is a diuretic and causes you to lose fluids and can potentially cause bladder infections from insufficient fluids leading to bladder inflammation. Even mild dehydration can initiate bladder infections.

How Do You Know If You’re Drinking Enough Water?

So how do you know if you’re drinking water in sufficient quantities? 

Well, you might think that the most obvious answer is, ‘Am I thirsty?’ It seems like common sense, right? Surprisingly, though, it might not be the most effective gauge. And here’s why.

First, research indicates that older people may be less sensitive[19] to the sensation of thirst. Second, we only feel thirsty if we are already dehydrated,[20] which means that we might already be experiencing negative side effects. And third? 

There’s a more effective option! 

The third and most effective solution is to simply check the color of your pee when you go to the bathroom! Stated in more scientific terms, this allows you to easily monitor your unique hydration status by tracking your urine concentration, every time you pass urine.

If you’re confused about what color your pee should be, this urine chart[21] covers a spectrum from good (clear) to mildly dehydrated (varying shades of yellow) to severe dehydration (brown). 

It is also vital to remember that your momentary circumstances can dictate whether you might need to increase fluid intake. According to the American Heart Association,[22] you may need to drink more depending on the climate (the humidity, as well as the temperature) if you are exercising, the intensity and duration of your exercise, and even which clothes you are wearing. Lost a pound of sweat through exercise? You’ll need to replace that[22] with a pint of water, as even mild dehydration can cause you to experience side effects.

Tips To Stay Hydrated

Many people find the taste and sensation of regular water a little bland, but there are many ways to make it more exciting and palatable! 

Bottled flavored waters can make the water feel a bit sexier – but be careful to read the nutritional label as many brands are often high in sugars or artificial sweeteners. A water bottle with an inbuilt fruit infuser might offer a great, healthy alternative for obtaining enough fluid – simply throw in your favorite blueberries, strawberries, lemon, lime, or fruit of choice, sit back, and enjoy!

Struggling to keep track of your water intake? You’re not alone. Researchers at the Harvard C.H.Chan School of Public Health came up with a solution by recommending filling a 20-ounce water bottle[23] four times a day to ensure that you’ve met your quota. 

Another great question? Whether you should be drinking bottled or tap water. The answer is that both have benefits, but bottled mineral water (surprisingly, perhaps), may not offer a noticeably healthful alternative. In fact, in a recent comparative study, Ulster University researchers found no statistically significant differences in the microbiological quality of tap and bottled water. They even reported that bottled water displayed a higher colony count[24] (an estimate of the bacterial count in colonies) than its tap-based counterpart!

You do not have to depend on the water you should drink, as there are other ways to increase your fluids. Consuming broth-based soups, jello, popsicles, cooked fruits, and other water-rich foods are all ways to get additional fluids in your body without actually drinking them.

If you’re looking to make your H₂O more exciting, another option could be to make your water sparkle (literally)! Sparkling water offers the same hydrating benefits as water in its most natural form. Carbonating water simply adds carbon dioxide to provide a little more pizazz, but it’s worth watching out for added sugars and artificial flavoring in branded and bottled versions. 

And for the athletes reading this, electrolyte-infused drinks can effectively help[25] to restore lost fluids and electrolytes as fast as possible, keeping you right at the top of your game and enabling you to maintain superior athletic performance. Liquid I.V., for example, provides a scientifically-developed ratio of glucose, potassium, and sodium that has been engineered specifically for optimal rehydration. It rapidly combats the effects of severe dehydration by providing an electrolyte mix that offers two to three times the rehydration properties of water, using cellular transport technology to speed up the hydration process. 

Final Thought

The question ‘How much water should I drink a day?’ is a great one. The answer, of course, is that your water intake must be tailored to your unique circumstances to remain as optimized as possible. Lifestyle-related factors (such as the local climate where you live and your exercise routine), health-related factors (e.g., if you have diabetes), personal goals (e.g., fat loss), and other physiological and genetic variables (such as gender, height, weight) can mediate exactly how much water you need to drink. 

But what we do know, in a general sense (and according to the US Centers for Disease Control and Prevention),[26] is that the average American only drinks about 3.9 cups of water daily – way below the recommended daily amount – so it’s a great idea for us all to reevaluate daily intake and ensure that we’re not missing out on any health benefits.

The bottom line is this. If you feel thirsty, you’re already dehydrated, obviously not drinking enough fluid and putting yourself in danger of chronic dehydration. So keep drinking those valuable cups of water in whatever style you choose – sparkling, still, bottled, tap, fruit-infused, ice-cold, or warmed-up! – and savor the benefits of this most humble yet powerful nutrient to remain as healthy and hydrated as you can.

+ 26 sources

Health Canal avoids using tertiary references. We have strict sourcing guidelines and rely on peer-reviewed studies, academic researches from medical associations and institutions. To ensure the accuracy of articles in Health Canal, you can read more about the editorial process here

  1. (2023). Drinking Water & Ground Water Kids’ Stuff > Water Facts of Life – Ride the Water Cycle With These Fun Facts. [online] Available at:
  2. (2019). The Water in You: Water and the Human Body | U.S. Geological Survey. [online] Available at:
  3. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. (2005). [online] Washington, D.C.: National Academies Press. doi:10.17226/10925.
  4. (2020). How much water should I drink during pregnancy? [online] Available at:
  5. Pross, N., Demazières, A., Girard, N., Barnouin, R., Metzger, D., Klein, A., Perrier, E. and Guelinckx, I. (2014). Effects of Changes in Water Intake on Mood of High and Low Drinkers. PLoS ONE, [online] 9(4), p.e94754. doi:10.1371/journal.pone.0094754.
  6. Haghighatdoost, F., Feizi, A., Esmaillzadeh, A., Rashidi-Pourfard, N., Keshteli, A.H., Roohafza, H. and Adibi, P. (2018). Drinking plain water is associated with decreased risk of depression and anxiety in adults: Results from a large cross-sectional study. World Journal of Psychiatry, [online] 8(3), pp.88–96. doi:10.5498/wjp.v8.i3.88.
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Elesa Zehndorfer

Medically reviewed by:

Kathy Shattler

Dr. Elesa Zehndorfer is an academic, a multi-award-winning writer, a Pilates coach and personal trainer, and author of five titles for a globally leading academic publisher. Dr. Zehndorfer earned her PhD from the School of Sport, Exercise & Health Sciences at Loughborough University in 2006. Her research interests focus on the application of physiology theory to both orthodox, and seemingly disparate, fields (such as finance, politics & management).

Medically reviewed by:

Kathy Shattler

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