Where it goes

See a wastewater treatment facility in action

Courtesy of The Royal Society, Sewage Works.

What is safe to flush?

Anything that isn’t “bio-waste” that makes its way into the sewer system creates big issues down the road–from costly clogs to pollution in our waterways. 

What is safe to flush? Remember the four Ps:

  • pee
  • poo
  • puke
  • paper (toilet paper to be more clear)


Lurking in sewers, fatbergs are a particularly costly phenomenon. These “fat icebergs” form when fats, oil, and grease are poured down drains then solidify with organic substances in human waste, creating a blockage within the sewer that grows by accumulating any non-biodegradable items like “flushable” wipes and diapers.

Preventing the next pandemic

Sewage can reveal a lot about the health of our communities. By collecting and testing waste–from treatment plants, sewage canals, even airport lavatories–epidemiologists can track viruses, bacteria, and disease, sometimes even before a case is reported.