1. Experts recommend you should drink at least two litres a day to keep adequately hydrated. The human body can survive about a month without food, but only 5-7 days without water. Water is vital to many bodily functions including cell structure maintenance, forming a solvent for chemical action and acting as a transport medium for nutrients and oxygen around the body, as well as white blood cells to fight infection and helping the body excrete waste products.
2. Drinking more water may help you lose weight. Scientists found people drinking 500ml of water increased the metabolic rate of fatty adipose tissue by 30% - enough to burn an extra 200 calories a day. Drinking water before and during meals can also take the edge off of your appetite and make you feel fuller and therefore less likely to overeat.
3. Drinking more water may help to protect you against cancer. There is some evidence that drinking adequate amounts of water may help protect you against three of the biggest killer cancers: large bowel, breast and prostate cancer.
4. A handy way to check if you are getting enough water. Pinch the back of your hand whilst resting it on a flat surface. When you release the pinch, the skin should snap back into place. If it is slow in doing this you are probably dehydrated.
5. Drink water even when you don't feel thirsty. Even at rest skin can lose up to half a litre of water into the atmosphere every day and during hot weather it will lose even more. By the time you feel thirsty your body has usually lost between 2 and 5 cups of water.

Sources of information:
- Expert Group on Hydration www.experthydration.com 
- Water UK www.water.org.uk/home/water-for-health/medical-facts
- Water Aid www.wateraid.org/uk/get_involved/drink_more_water/1412.asp