Water improves kidney function.
Your kidneys are one of your essential organs, and one of the busiest parts of your body. They maintain the cleanliness of your blood, filtering out excess water and waste products. They also ensure a balance of salt and other substances. Not drinking enough water places a higher workload on your kidneys to dissolve minerals and nutrients and remove waste. Good hydration keeps your kidneys in good condition.
Hydration helps prevent kidney and bladder stones.
Dehydration can cause your urine to become more concentrated, which shows that waste products in your system are not being filtered out efficiently. If the concentration of these waste products is high enough then they form crystals, which in turn can form into stones in the kidneys and bladder.
Staying hydrated prevents infection.
When bacteria form in the urethra (the tube through which urine leaves the body), they can cause Urinary Tract Infections (UTIs) - the second most common infection in the human body. These infections can then spread from the bladder up to the kidneys. Maintaining good levels of hydration ensures more urine, which enables your body to clean out bacteria which can cause infection.