Inflow in a sewer system can be detected by what method?

Inflow in a sewer system refers to the unintended entry of water, usually from surface runoff, groundwater, or other extraneous sources, into the sewer system. The correct method for detecting inflow is smoke testing. This technique employs non-toxic smoke that is blown into the sewer pipelines. When there are inflow problems, the smoke will escape through defects, such as cracks and openings, which helps to identify locations where external water is infiltrating the system.

This method is particularly effective because it enables operators to visually confirm the entry points of additional water without the need for extensive excavation or disruption of the system. The visibility of smoke escaping from the sewer system during testing offers an immediate and clear indication of areas that require repair or investigation.

Other methods like visual inspection can be more subjective, as they may rely on external observations that might not reveal hidden inflow issues. Voltage testing and pressure sensing are generally not related to detecting inflow; they are used for other purposes, such as evaluating electrical systems in pumps or measuring pressure in the lines but do not directly assist in identifying sources of inflow into sewer systems.