Most of the body is made up of water. Water acts as a solvent, a lubricant, a medium of transportation, and it is important in regulating our body temperature. And most of us don't drink enough of it.
If your joints are creaky, chances are you're dehydrated. Drink some water. Your joints need water for lubrication.
Fatigue, poor digestion, toxicity, heartburn, poor memory, poor kidney and liver function, bad skin, etc. can all be caused by you not getting enough water. Of course, there could be other causes for these and other conditions, but a lot of ailments could be easily taken care of simply by consuming enough water.
Dr. F. Batmanghelidj in his excellent book, "Your Body's Many Cries For Water" states that physicians often treat the symptoms with drugs or other treatments when the cause is simply dehydration. I highly recommend this book.
How much water should one drink? That depends on who you ask. Some say half your body weight in ounces of water each day. For me that would be 78 ounces. From personal experience, that isn't enough. Others say your full weight in ounces per day. So if you're not used to drinking a lot of water, cut out the sodas and all the other garbage (you should do that anyway) and start with half your body weight. Go up from there.
I generally drink around a gallon of water each day. Several years back I bought a water distiller. I also bought some one gallon polycarbonate jugs that aren't suppose to leach anything into the water like plastic does. Every morning upon rising, I do a few exercises to get me going and drink a 16 ounce glass of water. By the end of the day, the jug is usually empty or pretty close to it. That's what works for me. If you're smaller than I am, you may need less. If you're bigger, you'll probably need more.
The bottom line is that water is essential for good health. And if you're like most Americans, you get your liquid from sodas, coffee , tea, or other beverages that are dehydrating and just aren't very good for you. And if you have any nagging health problems and you're like most people in this country, chances are you just need to drink more water. So get a glass and drink up. It's for your health.