Where does the water go when we flush?

When you flush, the water travels from your toilet into household drains, then through underground sewers to a wastewater treatment plant. There, solids are removed, helpful bacteria break down dissolved waste, and disinfecting steps kill germs before the cleaned water is released to a river, lake, or sea.

The clever bend beneath the toilet keeps a small pool of water standing guard, so sewer smells cannot wander back into the bathroom. The same water keeps cycling through rain, rivers, pipes, plants, and taps, which means today's bathwater has a very long history.