Final answer:
Adults typically lose 2 to 3 liters of water each day through urination, perspiration, and breathing, which the kidneys help regulate.
Step-by-step explanation:
On average, adults lose 2 to 3 liters of water daily through processes such as urination, perspiration, and breathing. This water loss includes both sensible and insensible losses, where insensible water loss refers to the water expelled through the skin and lungs without our direct awareness. The kidneys play a critical role in regulating water balance, conserving water during dehydration, and expelling excess water when necessary.