Which of these is a primary source of unwanted groundwater entry into sewer systems?

Cracks or defects in pipes are a primary source of unwanted groundwater entry into sewer systems because these imperfections allow groundwater to infiltrate the sewer lines. When there are cracks, holes, or other structural defects in the sewer pipes, groundwater pressure can cause water to seep into the system, which can lead to several issues such as increased treatment costs, reduced system efficiency, and potential environmental harm.

The presence of groundwater in sewer systems is problematic because it can overwhelm the capacity of the treatment facilities, leading to potential overflows or backups. Furthermore, the mixing of groundwater with wastewater can complicate treatment processes and increase the risk of pollution.

While stormwater runoff and surface water drainage can contribute to the overall issues of excess water in sewer systems, they generally do not infiltrate existing pipes in the same way that cracks or defects do. Household wastewater is a part of the intended flow in sewer systems and does not typically contribute to unwanted groundwater entry. Therefore, identifying and repairing cracks or defects in pipes is essential for maintaining the integrity of the sewage collection system and preventing groundwater infiltration.