Pittsburgh Water continues to make investments in innovative technologies and solutions that will help us deliver on our promise to update aging infrastructure and protect public health and the environment, all while minimizing disruptions to our customers.

As part of our South Side Flats Sewer Rehabilitation project, taking place between South 18th Street and South 21st Street in the South Side Flats, Pittsburgh Water has chosen one such method to employ, known as trenchless sewer installation or sewer microtunneling. 

Upon completion, this sewer rehabilitation project will ultimately separate the combined system and create dedicated storm and sanitary sewers on several streets in South Side Flats, meaning more reliable sewer service for our customers.

Combined sewers carry both stormwater and sewage, which can overtax pipes during heavy rain events. These storm events can cause basement backups, overland flooding, and polluted waterways in our region. 

This is where sewer microtunneling comes in. To install the new sewer, contractors bored a 48-inch hole under the street, where the new sewer pipe will be pushed into place. This “trenchless” construction process results in a much smaller excavation area during construction. Only two pits – for pipe entry and exit – are required.

The project was not always intended to be performed this way. Original project plans included digging a trench down most of Wharton Street to separate the existing sewer infrastructure. However, space restrictions – including how deep the pit would need to be dug to properly install the sewer and how narrow the streets are in the area – made it more feasible to use a trenchless method. Not only is microtunneling more efficient, it's also less disruptive to residents. In fact, we’re ahead of our planned schedule for this phase of the project!

Upon installation of the new sewer, Pittsburgh Water will connect all properties with splashing downspouts, and extend storm laterals to the edge of the roadway for remaining properties. As part of our commitment to water quality, we'll replace any lead service lines found in the project area via the federally funded Neighborhood Lead Line Replacement Program.

For more information on this project please see our project webpage.