How much water do you really need to drink?

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There’s nothing new about the idea that drinking water is good for your health. However, from the gallon-a-day-of-water TikTok challenge to the Stanley Quencher being the hottest accessory to carry around, it does seem as though hydration is at the forefront of people’s minds more than ever. But how much water do you really need? 

Some people say you need to drink eight glasses a day, others say more than that and then others say less. For the sake of clarity, we spoke with two nutritionists to get to the bottom of how much water you should be drinking per day. We also asked them why it’s important to stay hydrated and for tips on how to make sure you get enough water. 

SKIP AHEAD How much water do you really need to drink? | What happens if you don’t drink enough water? | Tips for incorporating more water into your routine

For many years, the common belief was that people should aim for eight glasses filled with eight ounces of water per day — this is commonly referred to as the “8×8 rule.” But that thinking has been debunked. Research published in the journal Science in November 2022 looked at 5,600 people across 26 countries and found that most people do not need to drink that much water daily to stay hydrated. The same study concluded that there is no one-size-fits-all recommendation for people. 

How much water an individual should drink depends on body size, physical activity and diet, says Emily Martorano, a registered dietician nutritionist and owner of Emily Morgan Nutrition. Generally, men tend to need more water than women. “A simple method to estimate how much water you should aim for is to divide your weight in half and drink that number in ounces per day,” says Martorano. But remember, this number is just an estimate. If you exercise frequently, live in a hot climate or have various medical conditions, you may need more water. 

You should also pay attention to the cues your body gives you. “Thirst is a natural indicator that your body needs more fluids,” says Francesca Alfano, a functional integrative nutritionist and founder of Francesca Alfano Nutrition. “The color of your urine can also be a useful gauge of hydration — if it’s light yellow or pale, you’re likely well-hydrated.” If you need help figuring out the right water intake for your body’s needs, you can always consult a doctor. 

Just like plants need water to grow, your body needs sufficient hydration. Not getting enough water in your diet can lead to dehydration, which has many unfortunate side effects. “Some of the common side effects of dehydration are constipation or other digestive complaints, low energy, brain fog, headaches and migraines and dry skin,” says Alfano. 

If you don’t get proper hydration over long periods, the impact on your body can worsen and lead to more severe health issues. “Prolonged dehydration can lead to serious health complications such as kidney stones, urinary tract infections and heat-related illnesses,” says Martorano. “All to say, ensuring adequate water intake is crucial for maintaining overall health and well-being.” 

If you struggle to drink water, you may have to make a solid effort to boost your hydration levels. “Interestingly, as individuals gradually increase their water intake, they often develop a heightened sense of thirst over time, making it easier to drink more water,” says Martorano. To help you out, we gathered tips from experts. 

“One of the best ways to get yourself to drink more water is to stick to a schedule and develop a routine,” says Alfano. “For example, make a goal to drink a glass of water first thing in the morning or before you leave for the day. You could also have a glass of water after all meals and snacks, and before bedtime. Developing this type of consistency will make it more likely that you develop long-term habits.” 

Carrying water with you throughout the day can also ensure you’re staying hydrated. A water bottle with a straw will make drinking more enjoyable and accessible, encouraging you to drink more, too, says Martorano. Below, find a few highly rated bottles that will keep your water cold, won’t spill if they tumble over and are portable.

Several apps can help you track your water intake. This can help keep you accountable. “Smartphone applications like Aqualert are designed to send reminders prompting regular hydration throughout the day,” says Martorano. Here are a few more popular water-tracking apps: 

• My Water: This iOS-compatible app is free, with some in-app purchases. You can enter your personal information (like height and weight) and the app will recommend how much water you should aim for per day. Then, you can track when you drink water and set daily reminders to ensure you hit your goal. 
• Hydro Coach: Available on Android devices, this app will help you set a daily goal and send you reminders throughout the day. It can also be customized if you are pregnant or breastfeeding. The app is free with in-app purchases for certain features. 
• Plant Nanny Tracker: This app adds a fun gaming component to tracking your water intake for iPhones and Androids. You can choose from various plant characters to plant and water as you drink water in real life. The more you consume, the faster your plant grows and the more achievements you get.  

At NBC Select, we work with experts with specialized knowledge and authority based on relevant training and/or experience. We also ensure all expert advice and recommendations are made independently and without undisclosed financial conflicts of interest.

Bethany Heitman is a contributor at NBC Select and a journalist who regularly covers beauty, home and lifestyle. For this story, she interviewed two nutritionists about how much water you really need to drink each day.