On November 15, the City of Redwood Falls passed an ordinance to start an Inflow & Infiltration (I/I) Reduction Program to reduce sanitary sewer overflows and sewer back-ups throughout the City.
What is Inflow & Infiltration?
Inflow is when clear water (ground, rain, or storm water) from illegal connections of sumps pumps, downspouts, and foundation drains is channeled directly into the sanitary sewer.
Infiltration is when groundwater seeps into sewer pipes via cracks or leaky joints.
What’s the Problem?
Because the sanitary sewer system was not designed to handle this excess clear water, it becomes overloaded during times of high groundwater or heavy rainfall. This can cause basement flooding or bypassing of raw wastewater to local streams and lakes. The excess clear water from I/I problems uses sanitary sewer capacity needed for wastewater. The result is sewer backups and increased costs for needlessly putting clear water through the wastewater treatment.
What to Expect
Throughout the next few years, I/I sources will be identified by one or more of the following methods in order to reduce city-wide basement backups that affects property owners and the City's sanitary sewer system:
- Sump Pump Inspections: verify sump pump discharges are not connected to the sanitary sewer system (see below for more information on the inspection process).
- Televising: video recording of the inside of public mains and private services to identify cracks, collapses, root intrusions, failed joints, and other potential sources of I/I. All public and private sanitary sewer service lines will eventually be televised.
- Dye Testing: non-toxic dye is injected into groundwater or surface water sources to monitor the sanitary sewer system.