Historic photo from 1926 of crews installing a sewer main Crews installing a sewer pipe in 1926

Our first sewer lines were built as early as 1840 in present-day Shadyside and Oakland. By 1908, more than 390 miles of underground sewer lines were in place, establishing the start of our combined sewer system that is still used today. Our sewer system includes 1,200 miles of sewer lines and more than 25,000 storm drains.

Approximately 75 percent of the sewer system is a combined system meaning that stormwater and wastewater flow through the same pipe. The remaining 25 percent is a separated system, which means that wastewater flows through one pipe and stormwater flows through another. 

We send wastewater – the water you flush down your toilet or water that goes down your drain to ALCOSAN, the regional wastewater treatment plant along the Ohio River. They treat wastewater for the 83 municipalities in Allegheny County, including the City of Pittsburgh.

How To Handle A Sewer Backup

It's never pleasant, but on occasion basements and sewers back up into homes and business throughout Pittsburgh. When this happens, you'll want to know what to do and who to call. Take the time to prepare by reading these helpful steps for handling a sewer backup

Follow Your Flush! 

ALCOSAN, 3 Three Rivers Wet Weather, and CivicMapper created the Flush It! tool. The tool shows the path wastewater takes to the ALCOSAN treatment facility from any address within their service area. Enter your address to follow your flush to ALCOSAN.