Inflow and Infiltration

Inflow and infiltration (I&I) is water that enters the sewer system through cracked pipes, leaky manholes, broken cleanouts, and improperly connected storm drains and down spouts.
Inflow generally comes from rain, while infiltration comes from groundwater.

Limiting inflow and infiltration minimizes the cost of treating wastewater and avoids overwhelming our lift stations and treatment facilities.

If the system becomes overwhelmed during a storm, sewage can back up and cause overflows, which can damage the environment and affect public health.

TCRSD constantly works to reduce inflow and infiltration in the following ways:

Smoke Testing:   Blowing smoke into a specific section of sewer pipe can indicate the location of a broken pipe, manhole, catch basin, or where roof or foundation drains might be connected to the sewer system. If smoke can escape from these places water can also get in, especially during storms.  

Dye Testing:  Dye can show inappropriate connections to the sewer system.  If dye is added to something like a storm basin that shouldn't be connected to the sewer system and then shows up in the sewer system, a connection is indicated and can be fixed.

TV Inspection:  We use a robotic camera to record a video of the inside of sewer pipes. Breaks anc cracks in main lines, root intrusion, leaking water, and general deteriorating conditions are noted and graded for repair.

Flow Monitoring: Sensors installed around the county are used to gather sewer flow information, which can show inflow and infiltration as they occur.