Rutland Water Stopper Hydraulic Cement stops flowing water leaks, even under pressure! Plug troublesome cracks in masonry to stop seepage in just minutes. This dry mix hydraulic cement is a fast-setting mixture that stops water flowing through cracks and breaks in masonry surfaces. Use it to repair swimming pools, cisterns, frost damage, basement walls, or water storage containers. It"s also perfect for use as anchoring cement to secure bolts and machinery. Very fast setting gray cementStops the flow of water in breaks and cracks even under pressureUse as an anchoring cementPromptly stops the flow of waterSets up in 3 to 5 minutes6200 psi compressive strength