THE WATER JOURNAL

How Much Water Should You Really Drink? Surprising Facts About Staying Hydrated

There is no single number of glasses that suits everyone. Daily water needs depend on your activity, environment, life stage and health. It also matters whether a guideline describes drinks alone or total water from drinks and food.

Why the eight-glasses rule is only a guide

The NHS suggests six to eight cups or glasses of fluid a day as a general guide. People may need more during prolonged activity, hot weather, pregnancy, breastfeeding or illness. This is not a fixed prescription, and a glass is not a standard volume. [1]

Total water is different from plain drinking water

Common adult figures of around 2.7–3.7 litres describe total intake, including food and other drinks. They should not be read as instructions to drink that quantity of plain water on top of everything else. Food often supplies about a fifth of total water intake, although this varies with diet. [2]

What affects your daily needs?

Exercise and heat increase fluid loss through sweating. Illness can also change your requirements. Existing health conditions and prescribed fluid limits need individual advice. A general formula cannot account for every circumstance. [2]

Which drinks count?

Water is a practical everyday choice. Milk, tea, coffee and other drinks also contribute fluid. Consider sugar and caffeine when choosing drinks. Fruit and vegetables contribute water too. [1]

Make regular drinking easier

Keep a bottle or glass within reach and drink regularly through the day. Plan access to drinks when exercising or spending time in the heat. The NHS uses pale-yellow urine as a general hydration cue. It is not a diagnosis or a replacement for medical advice. [1]

More is not always better

Forcing large amounts of water can be harmful. Follow any fluid restrictions from your healthcare team. During significant vomiting, diarrhoea or other fluid loss, ask a healthcare professional about appropriate treatment and rehydration. [2]

Explore the practical guides

Read about hydration during exercise or compare bottle and case sizes for your routine. Bottle size is a shopping choice, not a daily intake prescription.