Sewer Cleanout and Manhole Installation in Maple Valley, WA

Soos Creek Water & Sewer District identified an aging sewer segment in Maple Valley that needed better access for maintenance, and Mighty Arm Excavation was brought in for two connected pieces of work: installing a new sewer main cleanout and replacing an undersized manhole with a 48-inch precast concrete structure. Both sat within an active residential street, so traffic control, utility locates, and trench safety planning had to be in place before any excavation began.

Crews opened the trench with a trench box for worker protection, adding benching or shoring as the soil conditions and the depth to the existing main required. The manhole base, riser, and cone sections were precast concrete, which allowed the structure to be set quickly and kept disruption to the street short. Each section was lowered into place by excavator and checked for alignment before the next was set, and new PVC pipe connections were tied into the existing line and checked for grade before backfill. The cleanout riser was installed at the new access point, giving future maintenance crews direct entry to the main without re-excavating. From initial excavation through structure setting, pipe tie-ins, and compacted backfill, the project took about four days.

See Maple Valley sewer infrastructure project for the same location.