Inspections of the wastewater infrastructure showed signs of deterioration, specifically to a number of manholes.  Structures suffered from a variety of issues.  Damaged flow channels where causing solids to backup, some manholes where having to be cleaned every week with a vacuum truck.  In other structures, leaks had washed the surrounding backfill material into the manhole, causing large voids outside the structure.  Digging and replacing each manhole would have been very costly, time consuming and disruptive to the community.


The city contracted with Underground Tech to rehabilitate the failing structures.  To restore the structural integrity of each manhole, the Mainstay Composite Liner was recommended for the project.  Active leaks were stopped by using injection grout and hydraulic cement. Large voids outside the manholes where filled with high strength mortar. Damaged channels where removed and rebuilt to facilitate flow.  After repairs where made, each manhole was lined the Mainstay Composite Liner.


Structurally sound manholes that are leak free and protected against corrosion without the need to dig and replace.

Cottage Grove, Oregon

Installation Date:
September 2019

City of Cottage Grove Public Works