How much water a day? The DGE guidelines explained simply
How much water a day do you actually need? Two litres, three litres, "as much as possible"? There are lots of numbers going around. The German Nutrition Society (DGE) gives a guideline of around 1.5 litres a day from drinks for adults. In this guide we explain where that figure comes from, how it differs by age, when you need more and how to keep track of it in everyday life – for example with a 500 ml bottle.
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The DGE guideline
The DGE publishes reference values for water intake. For adults, the recommended intake from drinks is around 1.5 litres a day. The word "drinks" matters: your body also gets water from solid food such as fruit, vegetables, soups or bread, and a small amount of water is produced by your metabolism. Total water intake is therefore higher than 1.5 litres.
According to the DGE, the values apply to a diet that meets energy needs and to average living conditions. They are a guideline for a normal day, not an exact rule for every person.
How much water a day by age?
The table below shows the DGE guideline values for water intake from drinks (source: DGE, reference values for water, dge.de). In the third column we have roughly converted the values into cups or 500 ml bottles.
| Age | Drinks per day | roughly equals |
|---|---|---|
| 1 to under 4 years | 820 ml | 4 small cups |
| 4 to under 7 years | 940 ml | almost 2 bottles of 500 ml |
| 7 to under 10 years | 970 ml | almost 2 bottles of 500 ml |
| 10 to under 13 years | 1,170 ml | just over 2 bottles |
| 13 to under 15 years | 1,330 ml | a good 2.5 bottles |
| 15 to under 19 years | 1,530 ml | about 3 bottles |
| 19 to under 25 years | 1,470 ml | almost 3 bottles |
| 25 to under 51 years | 1,410 ml | almost 3 bottles |
| 51 to under 65 years | 1,230 ml | just over 2 bottles |
| 65 years and older | 1,310 ml | a good 2.5 bottles |
| Pregnant women | 1,470 ml | almost 3 bottles |
| Breastfeeding women | 1,710 ml | almost 3.5 bottles |
The often-quoted "1.5 litres" is therefore an easy-to-remember rounding for adults. For everyday planning, that is perfectly sufficient.
Where does the "two to three litres" figure come from?
Many people believe you have to drink at least two or three litres of water. Often, total water intake is confused with the amount from drinks. If you add the water from food and metabolism, adults reach well over 1.5 litres in total according to the DGE reference values. Only part of that has to be drunk, though. If you exercise on a hot day, you will of course need more – on a quiet office day in winter, you won't.
Special groups
For older people, fluid intake is often a particular issue, because the sense of thirst can decline with age. A fixed routine helps more than waiting to feel thirsty. The DGE gives separate, higher values for pregnant and breastfeeding women (see table). Children need less, but they easily forget to drink while playing – so parents should offer drinks deliberately.
When you need more
Your fluid intake is not a fixed value for every day. According to the DGE, needs increase with, among other things:
- high energy expenditure, for example physically demanding work or sport,
- heat,
- dry, cold air,
- fever, vomiting or diarrhoea.
On top of that, there are situations in which you sweat a lot, such as in the sauna. If you do several sauna rounds, replace the lost fluid during the breaks and afterwards. Exactly how much that is depends heavily on the person, duration and temperature – which is why we deliberately give no blanket figure here. When it's best to drink is explained in our article on cooling down: Cooling down after the sauna.
What counts towards your fluid intake?
In principle, all drinks count towards your daily intake. Water – including tap water – and unsweetened herbal or fruit teas are considered ideal. According to the German consumer advice centre (Verbraucherzentrale), coffee and black tea in normal amounts count too.
Less suitable as thirst quenchers are:
- Juices and soft drinks: contain a lot of sugar. Better to mix juice with plenty of water.
- Alcohol: does not count as a thirst quencher.
- Energy drinks: lots of sugar and caffeine, not meant for quenching thirst.
Water from food is not included in the table above. If you eat a lot of fruit, vegetables or soup, you take in additional fluid that way.
How to tell whether it's enough
Having an exact number in your head matters less than paying attention to a few simple signs. Common indicators are:
- Thirst: it signals that your body needs fluid. However, the sense of thirst often declines with age.
- Urine colour: light, straw-coloured urine is considered a good sign. Very dark urine can indicate too little fluid.
- How you feel: headaches, tiredness or poor concentration can have many causes – not drinking enough is one of them.
If you are unsure or have symptoms, talk to your doctor.
Can you drink too much?
For healthy adults, this is rarely an issue in everyday life. Very large amounts in a very short time can become a problem. Things are different with certain conditions, such as heart or kidney disease: here a fluid intake set by your doctor may apply that differs from the general guidelines. In that case, your doctor's advice always applies, not a blog article.
How to plan your intake with a 500 ml bottle
The guideline becomes most tangible when you convert it into bottle fills. 1.5 litres is exactly three fills of a 500 ml bottle. A possible daily routine:
- Morning: fill the bottle with water or tea and finish it by lunchtime.
- Midday: second fill for the afternoon.
- Evening: third fill, spread over dinner and the evening.
Add coffee, a glass with your meal and soup – and you're well covered on most days. An insulated bottle has an advantage here: tea poured in the morning is still warm at lunchtime, and cold water stays cool in summer. According to the manufacturer, our IZY bottles keep drinks hot for up to 12 hours and cold for up to 24 hours.
Both models in our shop – the IZY Bottles Van Gogh Flowers thermos bottle and the IZY x Pip Studio "La Dolce Vita" thermos bottle – hold exactly 500 ml, are double-walled stainless steel, BPA-free and taste-neutral. You'll find them in our IZY collection.
Related reading: Drink more water: 10 tips that really work in everyday life · Drinking in winter: why it is harder and what helps · 500 ml water bottle: which size suits your everyday life?
Conclusion
How much water a day you need can be answered well for adults with the DGE guideline of around 1.5 litres from drinks – that's three fills of a 500 ml bottle. In heat, during sport, in dry air, when ill or in the sauna, you need more. Children, teenagers, older people, pregnant and breastfeeding women have their own guideline values. And if you have a condition in which fluid intake plays a role, check with your doctor.
Frequently asked questions
How much water a day does the DGE recommend?
For adults, about 1.5 litres from drinks. Water from solid food comes on top.
Are two to three litres better?
Not automatically. You mainly need more in heat, during sport or when sweating heavily. On normal days, the DGE guideline is a good orientation.
Do coffee and tea count?
Unsweetened tea definitely does. According to the Verbraucherzentrale, coffee in normal amounts also counts towards your intake.
How much should children drink?
Depending on age, according to the DGE between about 820 ml (1 to under 4 years) and 1,330 ml (13 to under 15 years) from drinks.
Does soup count towards fluid intake?
Soup provides fluid but counts as food, not as a drink. So it comes on top of the DGE values for drinks – a nice bonus, not a replacement.
Does the guideline also apply to heart or kidney disease?
Not necessarily. With such conditions, a different fluid intake may be appropriate – please check with your doctor.
Personally written by Martin – founder of BeachAndSteam and sauna operator at Lake Kulkwitz for more than 18 years.