STORMDRAIN/IMPERMEABLE SURFACE ⇨ CSO

What’s the story?

Swoosh! When water flows as runoff from a roadway or parking area, it moves downhill with the force of gravity, and then often down a storm drain into an underground stormwater and sewage system. In some places, especially cities, stormwater mixes with the water used by people (sewage) and this combined water travels to the wastewater treatment plant to be processed. The good news: the pollution carried by runoff can be filtered out and cleaned, rather than ending up directly in a body of surface water and harming the environment! The bad news: when there is a big storm, the whole system can overflow from too much water and untreated sewage is released into the environment (yuck)! This is called a CSO - combined sewage overflow.

Click on your water drop above to travel to the CSO next!!