Inflow & Infiltration Municipal Information
How a Municipality Reduces Known Sources of I&I
The municipality takes steps to identify sources of I&I in its sanitary sewers. Once identified, the sources are incorporated into the municipality’s long-term maintenance and capital projects plans. This allows for the reduction of I&I and the elimination of sewer overflows in a cost-effective manner.
Municipalities use the following techniques to reduce and eliminate sources of I&I:
- Replacing or rehabilitating the defective sewer pipe, lateral and/or manhole
- Pipe grouting – using a cement-based grout to fill a hole or crack in a pipe or manhole
- Pipe relining – inserting a flexible liner into a defective sewer pipe or sewer service lateral which hardens into an impervious surface
- Disconnecting known inflow sources, such as cross-connected catch basin drains, footing drains or rainwater leaders
- Installing drainage systems that will allow cross-connected sewers to be separated