We know that water is one of the most primary components of the human body, and it makes up from 60% to 70% of your body by weight. Not only that, but water is a vital part of nearly every system and organ; without a sufficient supply of water, the body simply cannot function properly. And understanding the importance of water toward our health well will help us to drink enough water and have a health body. 
It is certain that blood, muscles, lungs, and brain all contain water and that the reason why you need water to regulate body temperature and to provide the means for nutrients to travel to your organs and tissues. It also helps transport oxygen to your cells, removes waste, and protects your joints and organs. Taking in too litter water or losing too much water leads to dehydration. You can recognize this by some following symptoms: thirst, pains in joints and muscles, lower back pain, headaches and constipation or tiredness, dry skin, and lack of concentration.
Water can be understood like a lubricant in the body : In digestion water serves as a lubricant and almost all other body processes. The water in our saliva helps facilitate chewing and swallowing, ensuring that food will slide easily down the esophagus. Water also lubricates our joints and cartilages and allows them to (pardon the pun) move more fluidly. When dehydrated, the body rations water away from the joints. Less lubrication equals greater friction and that can cause joint, knee and back pain potentially leading to injuries and arthritis. Even our eyeballs need plenty of lubrication to work well and remain healthy.
Like a car cannot drive without gas and oil, our body is the same. Without water we cannot live, the fact that, all the cell and organ functions that make up our entire anatomy and physiology depend on water for their functioning. So the question is that how much water do you drink a day is good for your health? According to some recent surveys, scientists say that drinking about 8 glasses of water is really enough and good for our health. However, this depends on your daily activities a lot.
For example, if you are an athletes, you have a heavy program and your body burns a lot of calories, you sweat a lot you will really need more water than people who do not do exercise. On the contrast if you drink a lot of milk and fruit juice, or you eat a lot of vegetable you need not drink 8 glasses of water everyday. These things mean that depend on your activity as well
your habits in eating and drinking you can adjust the quantity of water you will drink a day to keep the body healthy.
The most important is that water is really cheap and has no calories as well added ingredients. Do not let your body is in dehydration but if this happens, drinking water is the best choice for rehydration. Drinking about 8 glasses of water a day is not difficult, because it is really easy to drink and you do not worry about overweight. Water will be not harmful for your body, of course drinking too much water is really dangerous. Drinking enough water will help you to have a health body as well a happy life.