Daily Water Intake: Guidelines for Children and Adults

Drinking Water Issues

Hello, may I ask: 1.
What is the normal daily water intake for a child (male, 8 years old)? 2.
What is the normal daily water intake for an adult? 3.
If we only drink RO (reverse osmosis) water at home and in the office, will this lead to insufficient mineral intake or electrolyte imbalance over time? I would greatly appreciate your response to these questions.
Thank you!

Lin Xiansheng, 40~49 year old female. Ask Date: 2020/07/23

Dr. Cai Xiuwen reply Nutrition

Hello! According to the recommendations from the National Health Administration, adults should drink 6-8 cups of water (240ml per cup), totaling approximately 1500-2000cc per day.
For elementary school children, the minimum daily water intake is at least 1500ml, consumed in small sips throughout the day.
However, the actual intake should be adjusted based on climate, physical activity level, health status, and lifestyle habits.
Depending on age, gender, weather, and physical exercise, the amount of water children need can vary significantly.

According to guidelines established by the European Food Safety Authority (EFSA), children aged 4 to 13 should drink about 6 to 8 cups of fluids daily, while younger children require relatively smaller amounts (for example, 150ml for a 4-year-old and 250ml for older children).
There is also a simple formula for calculating water intake:
- Adults: 30-35cc of water per kilogram of body weight
- Children: 50-60cc of water per kilogram of body weight
- Infants: 150cc of water per kilogram of body weight
Reverse osmosis (RO) water typically removes salts, manganese, iron, fluoride, lead, and calcium.
Most mineral components in water are physically larger than water molecules and are filtered out by a semi-permeable membrane during reverse osmosis.
However, the majority of the minerals needed by the body are obtained from food rather than drinking water, so there is no need to worry about the impact of RO water on mineral intake.

Wishing you peace and health.
This information is provided by Dietitian Tsai Hsiu-Wen from Nantou Hospital, Ministry of Health and Welfare.

Reply Date: 2020/07/23

More Info

When it comes to daily water intake, both children and adults have specific recommendations that can vary based on several factors, including age, weight, activity level, and climate.
1. Daily Water Intake for Children (8-Year-Old Boys): According to guidelines from health authorities, an 8-year-old boy should ideally consume about 1.5 liters (or approximately 6-8 cups) of water daily. This amount can vary based on individual needs, such as physical activity and environmental conditions. The European Food Safety Authority (EFSA) suggests that children aged 4 to 13 years should drink about 6 to 8 cups of fluids per day, which includes water, milk, and other beverages. A simple formula for calculating water intake is to provide 50-60 ml of water per kilogram of body weight for children. Therefore, if an 8-year-old boy weighs around 25 kg, he would need approximately 1.25 to 1.5 liters of water daily.

2. Daily Water Intake for Adults: For adults, the general recommendation is to drink about 2 to 3 liters of water per day, which translates to roughly 8-12 cups. This can vary based on factors such as body weight, activity level, and climate. A common guideline is to consume about 30-35 ml of water per kilogram of body weight. For instance, a 70 kg adult would need approximately 2.1 to 2.5 liters of water daily. It’s important to note that these recommendations include all fluids consumed, not just plain water.

3. Impact of Drinking RO Water: Reverse Osmosis (RO) water is purified water that has had most of its minerals removed. While it is safe to drink, there is a concern about long-term consumption and potential mineral deficiencies. Most essential minerals, such as calcium, magnesium, and potassium, are primarily obtained from food rather than water. Therefore, if a balanced diet is maintained, the risk of mineral deficiency from drinking RO water is minimal. However, individuals who rely heavily on RO water without adequate dietary intake of these minerals may experience imbalances over time. Additionally, RO water can sometimes lead to an electrolyte imbalance if consumed in excessive amounts without sufficient dietary electrolytes.
In conclusion, while the daily water intake recommendations provide a good baseline, individual needs can vary significantly. It is essential to listen to your body and adjust your fluid intake based on thirst, activity levels, and environmental conditions. For children, encouraging water consumption through fun activities or flavored water can help them develop a habit of drinking enough fluids. For adults, maintaining a balanced diet rich in minerals can mitigate any potential risks associated with drinking RO water. Always consult with a healthcare professional if there are concerns about hydration or dietary intake.

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