Do Tea and Coffee Count Towards Water Intake? The Surprising Hydration Truth

October 14, 2025 •

4 min read

For many years, the belief persisted that caffeinated beverages like tea and coffee were dehydrating due to their diuretic effect. However, modern research has largely debunked this myth, revealing that in moderate amounts, these drinks do count towards water intake and contribute positively to overall hydration.

Quick Summary

Yes, moderate consumption of coffee and tea contributes to your daily fluid goals because their water content outweighs the mild diuretic effect of caffeine, especially in regular drinkers.

Key Points

Moderate Intake Counts: In moderate amounts, both tea and coffee contribute to your daily fluid intake, debunking the old myth that they are dehydrating.
Caffeine's Effect is Mild: The diuretic effect of caffeine in regular drinkers is mild and does not cause a net fluid loss, as the water content of the drink is greater.
Herbal Tea is Excellent for Hydration: Caffeine-free herbal teas are just as hydrating as plain water, making them an ideal choice for varying your fluid intake.
Additives Matter: Excessive sugar in coffee and tea can counteract hydration. Opt for plain beverages to maximize their hydrating benefits.
Plain Water is Still Best: While coffee and tea hydrate, plain water remains the best option for calorie-free and additive-free hydration.
Tolerance Plays a Role: Regular consumers of caffeine are more tolerant to its diuretic effects, meaning the impact on fluid balance is minimal.

Debunking the Dehydration Myth

For decades, the common advice was to avoid coffee and tea for hydration, under the assumption that caffeine acts as a powerful diuretic that causes more fluid loss than gain. While caffeine is a diuretic, its effect is often exaggerated and misunderstood. Studies show that the fluid contained within a typical cup of coffee or tea more than compensates for any minor fluid loss caused by the caffeine, particularly for individuals who consume these beverages regularly and have built a tolerance.

A 2014 study published in PLOS ONE provided strong evidence that moderate coffee intake provides similar hydrating qualities to water in regular coffee drinkers. This was a significant finding that helped to cement the new understanding that coffee and tea are not the dehydrating culprits they were once thought to be. The key word, however, is 'moderate.' Extremely high doses of caffeine can still have a more noticeable diuretic effect, which is why excessive intake is not recommended for maintaining optimal hydration.

The Difference Between Caffeinated and Herbal Teas

The world of tea offers even more variety when it comes to hydration. This is especially true for herbal teas, which are naturally caffeine-free and therefore lack any diuretic properties associated with their caffeinated counterparts.

Herbal Teas: Pure Hydration

Because herbal teas are infusions of herbs, spices, or other plant parts in water, and contain no caffeine, they are just as hydrating as plain water. Examples include chamomile, peppermint, rooibos, and ginger tea. For those who want to vary their fluid intake without consuming caffeine, herbal tea is an excellent choice. This also makes them ideal for hydration later in the day or for individuals sensitive to caffeine.

Caffeinated Teas: A Hydrating Contributor

Different types of tea made from the Camellia sinensis plant (such as black, green, and oolong) contain varying levels of caffeine, but all are still largely hydrating in moderate amounts. A cup of black tea contains less caffeine than a cup of coffee, and green tea even less. The amount of fluid in a single serving easily offsets the mild diuretic action of the smaller caffeine dose, meaning these beverages still contribute to your daily fluid tally.

The Best Choice for Optimal Hydration

While the hydrating properties of tea and coffee are a welcome discovery, it's crucial to understand that they are not a perfect substitute for plain water. For optimal hydration, water remains the gold standard.

Water vs. Caffeinated Drinks: A Comparison


Feature	Plain Water	Caffeinated Coffee	Caffeinated Tea	Herbal Tea
Hydration Potential	Excellent	Good (in moderation)	Excellent (in moderation)	Excellent
Caffeine Content	None	High	Moderate/Low	None
Diuretic Effect	None	Mild (in regular users)	Mild (in regular users)	None
Calories & Sugar	None	Varies (additives)	Varies (additives)	None
Ideal for All-Day Intake?	Yes	Moderation Recommended	Moderation Recommended	Yes
Key Benefit	Pure, calorie-free hydration	Antioxidants, mental alertness	Antioxidants, sustained energy	Flavor without caffeine/sugar

The Problem with Additives

The hydrating quality of coffee and tea is also highly dependent on what you add to them. A plain cup of black coffee or tea is mostly water. However, a large, sugar-laden Frappuccino or a heavily sweetened iced tea can be counterproductive to hydration goals. The body uses water to process excess sugar, and high sugar intake can lead to dehydration. Therefore, to maximize the hydrating benefits, it's best to enjoy these beverages without excessive sugar or cream.

Practical Tips for Balancing Your Fluid Intake

To ensure you meet your daily fluid needs, incorporating a variety of beverages is a practical approach. Here are some actionable tips:

Prioritize Plain Water: Start and end your day with a glass of water. Keep a water bottle with you and sip throughout the day.
Stay in Moderation: Stick to 3-4 cups of coffee per day to avoid the more significant diuretic effects that can occur with high caffeine doses.
Enjoy Herbal Teas: When you want a flavorful, caffeine-free alternative, turn to herbal teas. They provide excellent hydration and a host of other potential health benefits.
Balance Caffeinated Drinks: For every cup of coffee or tea, consider also drinking a glass of water to ensure you are staying adequately hydrated.
Watch the Add-ins: Opt for plain coffee and tea or use minimal sweeteners and cream to avoid counteracting the hydrating effects with sugar.

Conclusion

The long-held notion that coffee and tea are dehydrating is an oversimplification. In reality, these beverages are mostly water and contribute positively to your daily fluid intake, provided they are consumed in moderation. While water remains the optimal choice for pure, calorie-free hydration, enjoying your favorite tea or coffee can be a flavorful and hydrating part of a balanced diet. It's time to put the old myth to rest and enjoy your morning brew without the worry of dehydration. For more information on dietary guidelines, the NHS offers comprehensive advice on what counts towards your daily fluid intake.

Frequently Asked Questions

No, moderate amounts of coffee do not dehydrate you. While caffeine is a mild diuretic, the fluid from the coffee itself is much greater, leading to a net hydrating effect, especially for regular coffee drinkers.

Plain tea, especially herbal and decaf varieties, is virtually as hydrating as water. Caffeinated teas, when consumed in moderation, also offer similar hydrating qualities because their water content outweighs the diuretic effect of their caffeine.

Moderate consumption is generally considered to be around 3 to 4 cups (about 200-400 mg of caffeine) per day for most healthy adults. Beyond this amount, the diuretic effect of caffeine may become more noticeable.

Yes, absolutely. Since decaffeinated coffee and herbal teas have minimal to no caffeine, they are excellent sources of fluid and count directly towards your daily intake, similar to plain water.

The belief stems from caffeine's mild diuretic property, which increases urine production. However, this effect is not strong enough to cause a net fluid loss, especially with moderate intake and regular consumption.

Adding sugar can affect hydration, as the body uses water to process it. For optimal hydration, it's best to consume plain beverages. Additives also add calories, which can be a consideration for many people.

While tea and coffee count towards your intake, plain water is still the best source of hydration. It contains no calories or additives, making it the purest form of fluid for your body.

No, an individual's tolerance to caffeine affects the diuretic response. People who regularly consume caffeinated drinks develop a tolerance, while those who rarely drink them may experience a slightly stronger diuretic effect.