Water. Have you ever thought about how useful water is? Probably not, since you use and drink it every day, it seems to be taken for granted.
I can't strees enough how important water really is to you. Your water needs depend on many things, your health, how active you are, and how much and what you eat.

No single formula truly fits everyone. Though, knowing more about your body's need for fluids will help give you an idea of how much water you need to drink daily.
Okay, before jumping into your daily water intake, lets start with 'why?' to intake it. Water makes up about 60 percent of your body weight. That's more than half of you! Every single system in your body depends on water. Water is great. It helps remove toxins out of your organs, it regulates your body temperature, it carries nutrients to your cells and it moists up your ear, nose and throat tissues.Water also protects your joints and organs. . Blood is mostly water, and your muscles, lungs, and brain all contain a lot of water.
Water water water. It's more than a half of you, and there's still such a thing as dehydration? Sounds a bit silly, doesn't it?
You lose water through urination, respiration, you lose close to an additional liter of water a day through breathing, and if you are very active, sweating.. Caffeine pills and
alcohol, result in the need to drink more water because this makes you lose a lot of fluids. Symptoms dehydration ( mild) include pains in joints and muscles (after a good work out this doesn't apply), lower back pain, headaches and constipation. A strong odor to your urine ( yep, stronger than normal ), along with a yellow or amber-like color, means that you might not be getting enough water. Note that riboflavin, a B vitamin, will make your urine bright yellow. Some medications can alter the colour too.
Now, how much water do you need? About twenty percent of the water you need comes from the food you eat. The rest will come from drinks. Water is probably the best choice, obviously, because sodas have sugar and calories, which if you were to drink the daily norm of water with soda, you're way better off eating two or three chicken breasts and actually gaining high quality protein, rather than empty 'soda' calories.
A little over two liters of of water a day ,together with water from your normal diet, will typically replace your lost water. The Institute of Medicine advises that men consume about 3 liters (13 cups) of total beverages a day and women consume 2.2 liters (about 9 cups) of total drinks a day.
You should make sure to have a bottle of water with you no matter where you are, at work, camping, driving a car, exercising. Water does sound a bit unexciting, and I bet you'll get bored soon. To fix that, you can add a little flavour to it, some lemon maybe. You can experiment, but make sure to watch for calories, you don't want to drink a lot of them, start gaining weight and not realise why you're gaining weight if your diet is the same.
In the end, the biggest indicator of the need for water is
thirst. It's there for a reason afterall, isn't it?