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 contains glomeruli that can become damaged over time from the extra wear and tear of processing too much water, potentially impairing excretion.