Drinking too much water can affect human excretion in several ways: 1. Ingesting excess water increases total blood volume, putting unnecessary strain on the heart and blood vessels. 2. The kidneys must work overtime to filter out the excess water from the bloodstream. 3. The filtration system in the kidneys, including specialized capillary beds called glomeruli, can become damaged over time due to the unnecessary wear and tear from filtering large amounts of water.