The Path Of A Flush: Interactive Map Shows Wastewater's Journey To ALCOSAN

Feb 10, 2020

When you flush the toilet in Allegheny County, chances are that the waste ends up at a facility just up the Ohio River from the McKees Rocks Bridge.

To track the waste's path from one's toilet to the Allegheny County Sanitary Authority, people can use Flush.It.  This interactive map directs users to type in an address that’s within the ALCOSAN service area. After several seconds, a bright turquoise line appears, tracing a flush's route.

“It’s really interesting to see how that path can cross over rivers multiple times, it really takes a wild ride throughout region,” said Emily Mercurio, CEO of Civic Mapper, the Pittsburgh-based geospatial technology company that created the tool.

Civic Mapper combined all the municipal sewer data within the ALCOSAN service area into one map. The company mapped the direction that sewage flows, and calculated approximately how long it takes waste to reach the treatment facility, where wastewater is screened, filtered and disinfected. The map's code is publicly available.

“It’s a great public education tool,” said Mark Wolinsky, the executive director of 3 Rivers Wet Weather. The nonprofit, which receives funding from both the county health department and ALCOSAN, collaborated with Civic Mapper on the project.

Users of Flush.It will note there is often significant variation as to how much time it takes for a flush to reach ALCOSAN. Wolinsky said this largely depends on rainfall and snow melt; during dry conditions, sewer flow is roughly one to two feet per second.

Flush.It also shows users how many miles, and through what neighborhoods and municipalities, a sludge of waste will travel.

“You’re able to see pretty exactly where these pipes are, where this infrastructure is. And when you flush the toilet, it’s going somewhere. It has a life after it leaves the house,” said Mercurio.

Which is something to consider the next time you might want to flush cotton balls, expired medicine or anything other than bathroom tissue … and traditional matter… down the toilet.