What does I & I stand for?

What does I & I stand for?

• A. Input and Interflow
• B. Inflow and Infiltration
• C. Inflow and Infusion
• D. Infiltration and Inflow

Answer: (B)

I & I refers to two sources of extra water that enter a sanitary sewer system: inflow and infiltration. Inflow is stormwater or surface water that directly enters the sewer system through things like storm drains, roof leaders, or improperly connected drains during rain events. Infiltration is groundwater that seeps into the sewer pipes through cracks, joints, or defective laterals, even without rainfall. Together, they add unwanted volume to the sewer flow, which can overwhelm the system, cause overflows, and raise treatment costs. The other terms listed aren’t standard for this concept—terms like input or infusion aren’t used in this context, and while some sources might refer to both components, the recognized pair in practice is inflow and infiltration, with inflow commonly listed first.