Severity

• Dehydration is classified as mild, moderate and severe. If you're an adult suffering from mild or moderate dehydration, you can treat yourself by drinking more fluids, according to the Mayo Clinic. Severe dehydration requires immediate medical attention.
  
  

Mild to Moderate

• With mild to moderate dehydration, your body no longer has the fluid it needs to keep you cool and eliminate waste. You sweat and urinate less. Your mouth becomes dry and your skin loses its plumpness.
  
  

Severe

• If you don't replace your fluids in time, your blood cells don't have the water they need to maintain proper volume. Your blood pressure will drop, which will cause you to become dizzy and confused. You may even faint. Organ failure can occur if left untreated.
  
  

Warning

• The Merck Manual states brain cells in particular are vulnerable to severe dehydration. If you're confused it means your dehydration has become severe. At this stage, you're at risk for becoming comatose.
  
  

Urine Watch

• If your urine is dark yellow, it's a sign that you're dehydrated. Urine in a well-hydrated body is clear or light yellow.