Does tea count as water? Black, green, herbal and iced tea

Yes, tea counts toward your daily water. Black and green tea contain caffeine, which makes you pee a little more, but a normal cup holds far more water than the caffeine takes back, and usually less caffeine than a cup of coffee. Herbal teas mostly have no caffeine at all and count just like water.

So the real questions about tea are about what comes with the water: how much caffeine your day adds up to, what the milk and sugar bring, and whether the last cup lands too close to bedtime.

Does tea dehydrate you?

No, not in the amounts most people drink. The idea comes from caffeine, which is a mild diuretic: for a while after you have it, the kidneys make a little more urine. That much is true. But the effect is small at everyday doses, and people who drink tea or coffee regularly seem to become partly used to it.

The research is not large, but it points one way. A small 2011 trial compared healthy men drinking several mugs of black tea in a day with the same men drinking the same amount of plain water. Their hydration measures came out much the same either way. It was one small study in one group, but it tested something close to how people really drink tea.

Health services agree in practice: the NHS counts tea and coffee toward the fluids you need each day. The story for coffee is much the same, with more caffeine per cup, and does coffee count as water covers it in full.

Black, green, white and herbal tea compared

Every kind of tea counts toward your fluids. What differs is the caffeine, and that varies a lot with the leaf, how much you use and how long you brew it. A strong mug of black tea left to steep for five minutes can hold much more than a weak cup dunked for one. Treat the column below as a rough guide, not a measurement.

For a sense of scale, the US Food and Drug Administration gives roughly 30 to 50 mg of caffeine for an 8 ounce cup of black or green tea, and roughly 80 to 100 mg for the same size of coffee. Most mugs hold more than 8 ounces, so a real mug of tea sits higher than that.

Herbal teas are not made from the tea plant at all. They are infusions of leaves, flowers, roots or fruit, which is why most have no caffeine. One caution: a few herbs are not advised in pregnancy or with some medicines. If either applies to you and you drink a lot of one kind, ask a pharmacist.

How many cups of tea a day is too many?

For fluids, there is no real limit to worry about. For caffeine, health bodies give a fairly consistent guide.

• Up to about 400 mg of caffeine a day for healthy adults, according to the US Food and Drug Administration. The European Food Safety Authority reached a similar figure.
• No more than 200 mg a day in pregnancy, the NHS suggests. If you are pregnant or breastfeeding, check with your doctor or midwife.
• Less if it doesn't suit you. Some people feel jittery or anxious, or notice a racing heart, on far less.

By the FDA's rough figures, that is a lot of cups of ordinary tea. In practice the limit comes sooner than the arithmetic suggests, because mugs are big, brews are strong, and tea often arrives on top of coffee, cola and chocolate.

A few things matter more than the caffeine for heavy tea drinkers:

• Sugar. Two sugars in each of six mugs adds up fast. Cutting down by half a spoon at a time is easier than stopping all at once.
• Iron. Tea drunk with a meal can reduce how much iron your body takes in from plant foods. If you have been told your iron is low, ask your doctor; a common suggestion is to have tea between meals rather than with them.
• Very hot tea. The International Agency for Research on Cancer classes drinking beverages very hot, above about 65 °C (149 °F), as probably carcinogenic. Letting a fresh cup cool for a few minutes is an easy habit.

Does iced tea or milk tea count as water?

Yes. The water in all of these counts. The extras are what differ.

• Homemade iced tea. Unsweetened and brewed at home, it is water with flavor and some caffeine. Iced herbal tea, from a jug kept in the fridge, is one of the easiest ways to drink more on a hot afternoon.
• Bottled iced tea. Often sweetened, sometimes heavily. Check the label for sugar and caffeine before it becomes an all-day habit.
• Milk tea. The milk counts toward your fluids too, and brings protein and calcium with it. Watch the sugar more than the milk.
• Chai. Black tea simmered with spices and milk counts like any milk tea. Café chai lattes are often made with a sweet syrup, so they can carry a lot of sugar.
• Bubble tea. Lovely, and closer to a dessert than a drink. Count it as a treat.

Fitting tea into a desk day

Tea suits a working day well. The kettle is a reason to get up, the brewing time is a built-in pause, and a warm mug slows you down for a minute. A few ways to make it work for your water as well as your mood:

• Caffeinated in the morning, herbal later. Have black or green tea early, then switch to herbal from the early afternoon. Green tea still has caffeine, so it is not the answer to a late afternoon cup if you sleep badly. What time to stop drinking coffee for better sleep shows how to work out a cutoff from your own bedtime, and it applies to tea the same way.
• A glass of water with each mug. While the kettle boils is a natural moment for it.
• A jug of cold herbal tea. Brew a few bags in the morning, let them cool, and keep the jug in the fridge for the afternoon.
• Keep the mug away from the keyboard. A cup of hot tea spilled across a MacBook is a bad day for both of you.

A water reminder that doesn't mind tea

If you want a nudge to drink through the day, Notchpals, a Mac app with reminder characters in the notch, sends one without caring what is in the cup. Its Water characters include Lolo, an axolotl in a permanently good mood, who asks about your first glass of the day, turns up now and then after that, and makes one visit in the 2 to 5 PM window, when a lot of people decide on one more caffeinated cup. Lolo has been puzzling over the same question about coffee, and lands somewhere less nuanced than the research.

LoloIs coffee water? It's mostly water! Oh. Not the same? Water, then!

Since Notchpals doesn't log what you drink, the answer is yours. A mug of rooibos earns Done as surely as a glass of water does. If the kettle has only just gone on, Later gives you 20 minutes before Lolo asks once more, long enough for a fresh mug to cool to drinking temperature.