Water

We use an absurd amount of water each and every day. Just as an experiment, use your sink stopper and see how much water is needed just to wash your hands one time.

Then consider the amount needed for multiple hand washes and teeth bushings a day. This isn't even factoring in drinking water, water needed for flushing, and showering. If you took a bath, you'll also need to add that. Some people also need to water plants.

The amount of water a single human contaminates on a daily basis is insane.