Do coffee, tea, milk and juice count as water?

2026-10-30

Yes, almost every drink counts toward your daily fluid intake, including coffee, tea, milk and juice. Studies that measured how much of a drink the body keeps found that tea, coffee, soft drinks, juice and even regular-strength beer hydrate about as well as water in the short term, and milk does better. The real reasons to favor water are sugar, calories and caffeine, not hydration.

What the health authorities say

Expert bodies have said this for years:

The US National Academies concluded that caffeinated beverages can contribute to daily water intake as much as non-caffeinated ones, and that there is no convincing evidence that caffeine leads to cumulative body water deficits (National Academies report announcement).
The UK's NHS says that water, lower-fat milk and lower-sugar drinks, including tea and coffee, all count toward the 6 to 8 glasses of fluid it suggests a day. It also recommends limiting fruit juice and smoothies to one small glass (150 ml, about 5 fl oz) a day because of their sugar (NHS: water, drinks and your health).

What the research measured: the beverage hydration index

The best direct comparison is a 2016 randomized trial by Ronald Maughan and colleagues, published in the American Journal of Clinical Nutrition (abstract on PubMed).

How it worked. 72 healthy, well-hydrated men each drank 1 liter of still water and, on other days, 1 liter of three other drinks, from 13 common drinks tested in total. Each liter was drunk over 30 minutes. Researchers then collected all their urine for the next 4 hours. The less you pee, the more of the drink your body kept. They compared each drink to water and called the result the beverage hydration index (BHI): water scores 1.0, and anything above 1 is retained better.

What they found:

Better than water: full-fat milk, skimmed milk and an oral rehydration solution (the kind used for diarrhea). These produced noticeably less urine, with a BHI of about 1.5 at two hours.
No different from water over 4 hours: coffee, hot tea, iced tea, cola, diet cola, sparkling water, orange juice, a sports drink and lager.

Why milk wins: drinks with more sodium, potassium, protein, fat or sugar leave the stomach more slowly and are held onto longer by the kidneys. Plain water is absorbed quickly and the excess is passed quickly.

Limits of the study

It's one well-designed trial, not the last word. Participants were young men who were already hydrated, fasting and resting; each drink was a single liter; and results may differ for women, older adults, or people who are dehydrated or exercising. And the index measures short-term retention, not health. Still, it fits everything else we know.

Coffee and tea: not the dehydrators they're made out to be

Caffeine does have a mild diuretic effect, especially if you're not used to it or take a large dose. But in normal amounts, the water in the cup more than makes up for it, and regular drinkers develop a tolerance.

A 2014 study in PLOS ONE tested this in daily life. Fifty men who habitually drank coffee had about four mugs of coffee a day for three days, then the same amount of water for another three days. Measures of total body water, blood and urine showed no meaningful difference between the coffee and water periods (Killer et al., 2014). The authors concluded that moderate coffee intake hydrates similarly to water in habitual drinkers. Again, all participants were men, so take it as good but not complete evidence.

The sensible limit for coffee is about caffeine, not fluid. For more on that, including how much caffeine is considered safe, see does coffee dehydrate you?.

Drink by drink: what to count

Count fully

Water, still or sparkling. Sparkling water hydrates just like still; see is sparkling water as hydrating as still water?.
Tea and coffee, hot or iced, ideally without much sugar.
Milk, which is one of the most hydrating drinks measured. Plant-based milks weren't tested in the hydration index study, but they're mostly water and can reasonably count too.
Herbal and fruit teas, which are essentially flavored water.

Count, but keep small

Fruit juice and smoothies. They hydrate, but they're high in sugar. The NHS suggests a maximum of 150 ml a day.
Sugary soft drinks. They hydrate as well as water, but bring sugar and calories with no nutrition. Diet versions avoid the sugar.
Sports drinks. Useful for long or intense exercise, unnecessary for most people at a desk. See sports drinks vs water.
Energy drinks. Often high in caffeine and sugar. Count the fluid, but watch the caffeine.

Don't count

Alcohol. Regular-strength beer was roughly neutral in the hydration index study, but wine and spirits contain more alcohol per sip and less water, and alcohol increases urine output. Most people should treat alcoholic drinks as not counting toward their goal and drink some water alongside them. See alcohol, dehydration and hangovers.

Optional: soup and other liquid foods

Soups, broths and smoothies are mostly water. Whether you log them is up to you. Many people leave them out and treat them as part of the water that comes from food, which already covers a decent share of your needs.

Why water is still the default

If almost everything counts, why bother with water? Because hydration isn't the only thing your drinks do.

No sugar, no calories. Sugary drinks are linked to weight gain and tooth decay; water has neither problem.
No caffeine ceiling. You can drink water at any time of day without affecting sleep.
Cheap and easy. Where tap water is safe to drink, it costs almost nothing.

A practical approach is to make water your main drink and let tea, coffee and milk fill in, with juice and soft drinks as occasional extras.

Tracking mixed drinks

If you track your intake, it's simpler to log every drink that counts rather than only plain water. Otherwise your numbers will look lower than they really are and you may end up drinking more than you need.

Water Tracker lets you log any custom amount, so a 250 ml mug of tea or a 330 ml can of sparkling water goes in as easily as a glass of water, from your iPhone, Apple Watch, a Home Screen widget or Siri. If you connect Apple Health, each entry is saved there as Dietary Water. What you count is your choice; the app just adds it up.

Bottom line

Coffee, tea, milk, juice and soft drinks all count toward your fluid intake. Milk is among the most hydrating.
Moderate caffeine doesn't dehydrate habitual drinkers; limits for coffee are about caffeine, not water.
Keep juice to about 150 ml a day and go easy on sugary drinks.
Don't count alcohol, and drink water alongside it.
Make water your main drink, then count everything else honestly.

This article is general information, not medical advice. If you have a health condition, are pregnant or take medication, ask your doctor how much you should drink.