How Much Water Do You Need to Drink?

Water is critical for life

Without it, life comes to an end rather quickly. Water is one of the body's most essential nutrients. People may survive six weeks without any food, but they couldn't live more than a week or so without water. Why? That's because water is the cornerstone for all body functions.

Water is the most abundant substance in the body, accounting for up to 75 percent of body weight. It helps keep body temperature constant at about 98.6 degrees and it transports nutrients and oxygen to all cells and carries waste products away. Water helps maintain blood volume, and it helps lubricate joints and body tissues such as those in the mouth, eyes and nose.

What affects fluid requirements?

Air temperature, humidity, a person's activity level and his or her overall health affect daily fluid requirements.

Fluid recommendations don’t just mean water intake, it means the fluid from fruits, vegetables and caffeinated beverages also. Most people think fluid recommendations mean simply water, so for most of us, we may receiving more fluid than we think we are, especially if the diet is rich in fruits and vegetables.

So, how much do you really need to drink?

The Dietary Reference Intakes from The Institute of Medicine recommend a total daily beverage intake of 13 cups for men and 9 cups for women. This amount is for generally healthy people living in temperate climates. Individual needs vary so some people can be properly hydrated at somewhat higher or lower levels of water intake. Also, keep in mind that this recommended amount may come from a variety of sources. It includes other beverages—even those containing caffeine—in addition to the water that you drink. When you're exposed to extreme temperatures—very hot or very cold—your body uses more water to maintain its normal temperature. Under these conditions, you may need to increase your fluid intake.

Caffeine and fluid recommendations

For someone who is accustomed to caffeine, more fluid is readily absorbed than compared to someone whose body isn’t accustomed to caffeine. So a non-coffee drinker who decides to have a cup or two of coffee will see a greater diuretic effect. The regular coffee drinker will absorb most of the coffee as fluid. Fluid recommendations include fluid from other beverages other than water and food. Notice that fruits and vegetables have a much higher water content than other solid foods. Their high water content helps keep the calorie level of fruits and vegetables low while their nutrient level remains high.

How to check your intake

Urine color is one of the most accurate indicators to see if one is achieving adequate fluid intake. The clearer it is, the more hydrated our bodies are.