The best fluid to drink is plain water, but it’s far from your only option. Tea, coffee, milk, fruit juice, sparkling water, and even broth all contribute to your daily fluid intake. Adult men need about 10 cups (2.6 liters) of fluids per day, while adult women need about 8 cups (2.1 liters), though exercise, heat, and pregnancy all push those numbers higher.
Water: Still and Sparkling
Plain water is calorie-free, cheap, and absorbed quickly. It’s the simplest way to meet your daily fluid needs. If you find plain water boring, sparkling water is essentially the same thing for hydration purposes. Despite concerns about carbonation and acidity, a study that tested sparkling water directly against still water found the two had about the same effect on tooth enamel. The one exception is flavored sparkling waters with added citric acid or sugar, which behave more like soft drinks than water.
Adding slices of lemon, cucumber, or fresh mint to still water can make it more appealing without adding meaningful calories or sugar.
Milk Hydrates Better Than Water
This surprises most people, but milk, both full-fat and skim, actually keeps you hydrated longer than plain water does. Researchers who developed a “beverage hydration index” found that milk scored higher than water, meaning your body retained the fluid longer before producing urine. The reason comes down to milk’s natural electrolyte content, particularly sodium and potassium, plus its protein and carbohydrates, which slow the rate at which fluid leaves your stomach. If you tolerate dairy, a glass of milk does double duty as both hydration and nutrition.
Tea and Coffee Count
Caffeine is technically a diuretic, meaning it increases urine production. But the fluid in a cup of coffee or tea more than compensates for that effect at normal intake levels. The FDA considers up to 400 milligrams of caffeine per day safe for adults, roughly four standard cups of brewed coffee. Below that threshold, caffeinated drinks contribute to your hydration just like water does.
Green tea offers some additional perks. Its natural plant compounds have anti-inflammatory properties, and regular consumption is linked to meaningful health benefits. A 2023 study found that drinking two to four cups daily lowered stroke risk by up to 24%. Research on middle-aged and older adults found that frequent green tea drinkers had a 64% lower risk of memory and concentration problems. A large Japanese study found that four or more cups per day lowered the risk of dying from type 2 diabetes complications by as much as 40%. Black tea and herbal teas also hydrate well, though they haven’t been studied as extensively for these extra benefits.
Sports Drinks and Electrolyte Beverages
Your body relies on four key electrolytes to manage fluid balance: sodium, potassium, chloride, and magnesium. These minerals help move water in and out of your cells, support muscle and nerve function, keep your heart rhythm steady, and stabilize blood pressure. You lose electrolytes through sweat, which is why plain water sometimes isn’t enough after intense exercise or prolonged heat exposure.
Sports drinks are designed to replace those losses, but for most everyday activity, they’re unnecessary. They hydrate at roughly the same rate as water in studies, and many contain significant added sugar. Oral rehydration solutions, the kind used for illness-related dehydration, scored highest on hydration indexes because of their precise electrolyte ratios. If you’re exercising for over an hour or sweating heavily, an electrolyte drink makes sense. For a normal day at a desk, water or tea will do.
Juice, Coconut Water, and Broth
Orange juice hydrates at the same rate as water and provides vitamins, but it’s also calorie-dense. A glass here and there is fine, but relying on juice as your primary fluid source adds up quickly in sugar. Coconut water is a natural source of potassium and makes a decent light electrolyte drink, though its sodium content is lower than dedicated sports drinks.
Bone broth and vegetable broth are underrated hydration sources, especially when you’re sick or in cold weather when you might not feel like drinking cold water. Broth contains sodium naturally, which helps your body hold onto fluid rather than flushing it straight through.
Fluids Worth Limiting
Sugar-sweetened beverages like soda, sweetened iced tea, energy drinks, and fruit punch do technically hydrate you, but the costs outweigh the benefits. Frequent consumption is associated with weight gain, obesity, type 2 diabetes, heart disease, non-alcoholic liver disease, tooth decay, and gout. A single 12-ounce can of regular soda contains around 39 grams of added sugar. The Dietary Guidelines for Americans recommend that children under 11 have no added sugar at all.
Alcohol is the one common drink that genuinely works against hydration. It suppresses the hormone that tells your kidneys to retain water, so you lose more fluid than you take in, particularly with stronger drinks. Beer scored similarly to water in hydration studies at low volumes, but anything beyond light consumption tips the balance toward dehydration.
Food Counts Too
About 20% of most people’s daily fluid intake comes from food rather than drinks. Some fruits and vegetables are almost entirely water by weight. Cucumbers are 96% water, celery is 95%, and watermelon is 92%. Soups, yogurt, and oatmeal also contribute meaningful fluid. On days when you’re struggling to drink enough, eating water-rich foods can help close the gap.
How to Tell If You’re Drinking Enough
The simplest check is your urine color. Clear or pale yellow urine means you’re well hydrated. Dark yellow or amber urine means you need more fluids. Other signs of dehydration in adults include extreme thirst, urinating less frequently than usual, tiredness, dizziness, and confusion. In young children, watch for fewer wet diapers, a dry mouth, no tears when crying, and skin that doesn’t bounce back quickly when gently pinched.
Your needs shift day to day. Hot weather, exercise, fever, vomiting, and diarrhea all increase how much fluid you need. Pregnant women should aim for about 9 cups daily, and those who are breastfeeding need around 10 cups. Rather than fixating on a specific number, pay attention to your body’s signals and keep a water bottle within reach throughout the day.