Sanitary Manhole Leak Repairs — City of Waterloo

Harnessed technician injecting a leaking manhole joint inside a City of Waterloo sanitary manhole
Client / Owner
City of Waterloo
Location
Waterloo, Ontario
Service
Groundwater Control & Mitigation
Completed
May 2016

The problem. Manhole LE58-7A, a 1200 mm diameter precast sanitary manhole at Frobisher Drive and Northland Road, was taking on groundwater at all three pipe penetrations — the 8-inch PVC inflow and outflow pipes and a lateral stub. Combined inflows measured approximately 10 litres per minute of clear groundwater entering the sanitary system.

The repair. We drilled and injected each leaking pipe penetration with water-activated polyurethane, cutting off the active flows. With the penetrations sealed, water began revealing itself through cracks in the riser sections — so those actively leaking cracks were drilled, injected, and sealed the same way. In total, approximately 55 litres of water-activated chemical resin were injected. Injection packers were removed, drill holes and penetrations were parged with hydraulic cement, and excess materials were disposed of off site.

The result. All observed active inflows were stopped and the structure was left with a clean, parged finish. Our follow-up report also flagged that the 8-inch sanitary sewer, while flowing normally, was partially filled with settlement and solids and recommended flushing within the year — the kind of honest observation we include even when it isn’t our scope.

Project photos

Active groundwater leak at a pipe penetration in a sanitary manhole before injection grouting
Before — groundwater running in through the pipe penetration and bench.
Injection ports and reacted polyurethane resin around a manhole pipe penetration during leak repair
During — injection ports set around the penetration, resin reacting with the inflow.
Sealed manhole pipe penetration after injection grouting with drill holes parged
After — penetration sealed, ports removed and parged.
SG Services van and traffic control set up at a manhole on a residential street in Waterloo
Single-vehicle mobilization on a residential street.

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