Stop leaks in seconds with Sakrete Leak Stopper Hydraulic Cement. Available in white or gray, our high-strength hydraulic cement is formulated for extremely rapid set time and superior performance — even underwater. Use our Hydraulic Cement Leak Stopper to seal active concrete and masonry leaks in basements, cisterns, retaining walls and foundations, or to plug holes in pools and water features. Its non-metallic composition prevents staining, making it ideal for visible areas where concrete is leaking. Pair with Sakrete Surface Bonding Cement for reinforcement of repaired walls.