Headache
Heartburn
Irritability and depression
Low back pain
Recurring or chronic pain
Stomach ache
water retention

Waiting for the signal of "dry mouth" to determine your body's need for water is not going to be an accurate indicator. The dry mouth is the last outward sign of extreme dehydration. Damage is occuring to the body before this symptom appears. Because of a gradually failing thirst sensation, the body becomes chronically and increasingly dehydrated.

How much water do you need?

This is a good place to start. People are different, so consider what is best for you. On the average you should drink 50-75% of your body weight in ounces daily. Sedentary people need 50%. Active people need 75%. Add 8-16 oz. more for dry climates or heavy exercise.

Examples:
150 lb. sedentary person would need 75 oz. of water (150 X 50%)
200 lb. active person would need 150 oz. of water (200 X 75%)

Poor Substitutes for Water:

Further injury is done when the sensation of thirst urges an intake of water, but sodas, tea, coffee, or alcohol-containing beverages are taken instead.. These beverages contain water, but also dehydrating agents. Not only do they eliminate the water contained in them, but they also eliminate water from the body's reserves.

Juices are not how God designed for us to have our fruit. The missing fiber is essential to help maintain blood sugar balance.

You Are What You Drink
Cohesion-Flexibility
Water creates internal cohesion for your body, giving your cells and organs the flexibility to be stretched and even strained within certain limits without rupturing or tearing. Every time you move, reach for something or stand up, water is helping to protect your organs from being torn in the process.

Temperature-Comfort
Water helps your body stabilize temperature and acclimate to temperature changes. Without sufficient water, the human body can undergo fatal overheating or cooling very quickly.

Solvency-Nutrition & Detoxification
Water also provides natural solvent properties, supporting the body in the great task of breaking down substances for use or disposal. Think of all the vitamins, minerals and nutrients flowing through your organs and into your extremities that allow you to function normally, as well as the detoxification your body carries out through the release of sweat, urine and other means. Without water, these processes would cease to function.