Infiltration occurs when groundwater seeps into sewer pipes through cracks, leaky pipe
joints and/or deteriorated manholes. Inflow is stormwater that enters the sewer system
through rain leaders, basement sump pumps or foundation drains illegally connected to
the sewer. The impact on treatment and maintenance costs is substantial, and many
wastewater crews prioritize identifying and mitigating sources of inflow and infiltration
(I&I) in their systems.
Take this quiz to test yourself on how much you know about inflow and infiltration. Then
challenge your co-workers to see who will rise as the I&I expert.