Earthen dams losing water can be injected with polyurethane grout to seal the leak paths. Here holes were drilled along the crest of the dam which enabled lances to be inserted. The lances were then hooked up to a pump and injected with Hyperflex. Hyperflex is a single component polyurethane grout that is moisture activated. Hyperflex is also NSF/ANSI/CAN 61 approved for contact with potable water. This method is less invasive and more cost effective than tradition repair methods. Grouting was performed by grouting contractor Sub-Technical, Inc.