Mitigation of the Risks of Inflow and Infiltration in New Sanitary Sewer Systems

Standard CAN/BNQ 3682-320
Mitigation of the Risks of Inflow and Infiltration in New Sanitary Sewer Systems

Inflow/Infiltration (I/I) in sanitary sewer systems is a chronic issue throughout Canada. Negative consequences of I/I include increased risk of flooding associated with sewer backup, multiple risks to the environment and risks to public health and safety.

I/I creates a lack of capacity in pumping stations and trunk sewer systems, hence limiting the potential for urban densification and additional developments in urban communities. I/I also increases life cycle costs of sanitary sewer systems and can reduce by many years the lifespan of infrastructure. Sanitary sewage treatment plants may experience negative impacts associated with wet weather peaking, and overflow by-passes at pumping stations. As well, secondary by-passes at sanitary sewage treatment plants present significant risk to surface water systems associated with sanitary sewer system overflows. Negative impacts of I/I are exacerbated by increasing urban populations, increasing urban density/infill development, and aging infrastructure. I/I is also expected to be affected by climate change.

This standard has been developed to complement the existing resources by providing comprehensive guidance to limit risk of I/I in new sanitary sewer system construction. For further information concerning occurrence of I/I in new sewer system construction in Canada, refer to the foundational document prepared to support the development of this standard: “Reducing the Risk of Inflow and Infiltration (I/I) in New Sewer Construction”.