How much water you actually need in a day

There is no single daily water target that fits everyone. In the Eatwell Guide, UK government advice is to aim for 6 to 8 cups or glasses of fluid a day, and the nhs.uk guidance treats that figure as a starting point rather than a fixed rule.

What counts towards your fluid intake

Water, lower-fat milk and sugar-free drinks, including tea and coffee, all count. The NHS also notes that some fluid comes from the food we eat, which is why fruit and vegetables add to the total. The clearest day-to-day check is colour: most people should drink enough for their urine to be a clear pale yellow.

When your needs go up

Guidance from the cdc.gov notes that the body needs more water in hot climates, during physical activity, and when running a fever or having diarrhoea or vomiting. The NHS adds pregnancy and breastfeeding, long periods of activity, and being ill or recovering from illness to the list of situations where more fluid is needed.

Why it matters

According to the CDC, drinking water helps the body keep a normal temperature, lubricate and cushion joints, protect the spinal cord and other sensitive tissues, and remove waste through urination, perspiration and bowel movements. It also notes that dehydration may bring unclear thinking, mood changes, overheating, constipation and kidney stones, and that plain water has no calories, so swapping a sugary drink for water reduces calorie intake.

Habits that make it easier

• Carry a refillable bottle and sip through the day rather than in one go.
• Serve water with meals and choose it when eating out.
• Add a slice of lemon or lime, or try sparkling water, if plain water is unappealing.
• Drink extra after sweating heavily, and keep fluid within reach when you are unwell.

The bottom line

Aim for roughly 6 to 8 glasses a day as a guide, watch the colour of your urine, and drink more in heat, during activity and when ill. This article is general information, not medical advice; ask a doctor about how much you should drink if you have a heart, kidney or other condition that affects fluid balance.