Flood Cleanup in Pittsburgh, PA

Flood cleanup in Pittsburgh requires understanding the interaction between three distinct water sources — river flooding from the Ohio, Allegheny, and Monongahela, groundwater seepage from the metro's many steep hillsides, and combined sewer backflow from the ALCOSAN system that serves most of Allegheny County. The riverine flooding risk, while moderated by upstream Army Corps of Engineers reservoirs since the catastrophic 1936 flood, still materializes during extreme events: the January 1996 ice jam flooding caused significant damage along the lower Allegheny in Millvale and Etna, and the 2004 flooding crested the North Shore staging areas. For the majority of Pittsburgh flood cleanup projects, the event is not a river flood but rather a combination of hillside groundwater and combined sewer backflow that inundates basement spaces in the city's thousands of row houses and single-family homes. ALCOSAN's consent decree with the EPA requires $2.5 billion in long-term control improvements, acknowledging the system's chronic overflow problem, but compliance is phased over multiple decades. Flood cleanup in Pittsburgh's hillside homes often involves contaminated water even when the source appears to be groundwater — the combined sewer system in these neighborhoods means that any backflow carries sewage.