Service laterals and lateral connections are often a source of significant infiltration. According to the EPA, as much as 60% of overflow comes from leaking service connections. Studies have shown that most infiltration into service lines occurs within a few feet of the mainline.
Lateral grouting is completed much like mainline grouting, except the packer has an inflatable bladder that extends up the lateral connection from the mainline. Once lateral bladder is fully inverted up the lateral, the mainline bladders are inflated. The top, ribbed portion of the lateral bladder expands, pushing against the pipe wall, while the bottom expands enough to create a thin annulus for the grout to travel. Grout is forced under pressure through the defects into the surrounding soil creating an impermeable barrier in the soil. After sealing is complete, the mainline bladders are deflated, the lateral plug is reinverted into the assembly, and the packer is moved to the next lateral in need of rehabilitation. Like mainline grouting, any residual cured grout left behind in the pipe will breakdown as it cycles through the system.