The purpose of the ³⁄₁₆-inch hole is to prevent the pump from being air locked. A pump that is air locked cannot pump water. When the pump is running, water should be shooting out of the hole. This hole should be drilled approximately 3 inches above the pump at a 45° angle directed downward, so the water that comes out of the hole will flow back into the sump pit. Some main pumps may require the ³⁄₁₆-inch hole as well. Check with the manufacturer of your main pump if it is required, or watch our installation videos.