The Waterloo Barrier^® is a groundwater containment wall formed of sealable steel sheet piling developed in 1989 by researchers at the Waterloo Centre for Groundwater Research, University of Waterloo.

The Barrier incorporates a sealable cavity at the interlocking joint between piles that can be flushed clean, inspected, and then sealed after the piles have been driven into the ground. The system allows for documentable quality assurance and a high degree of quality control. Bulk wall hydraulic conductivities of 10^-8 to 10^-10 cm/sec have typically been achieved in testing conducted by the University, the U.S. Air Force, and others.

The Waterloo Barrier^® can be used to prevent off-site migration of contaminated groundwater or soil gases, or can be installed to isolate a site while remedial actions are in progress. It can also act as a structural wall during excavation or assist with site dewatering on civil engineering projects.