Waste products and excess fluid can build up inside the body without excreting from the kidney is the amount of water is not there in kidneys. Drinking plenty of water reduces the risk of UTI and keeps kidney healthy. H2O helps prevent kidney stones and UTIs. Kidney stones and urinary tract infections (UTIs) are two common medical conditions that can hurt the Kidney, and for which good hydration is essential. Drinking enough water also helps produce more urine, which helps to flush out infection-causing bacteria.