The couplings should have a watertight gasket seal. When pipe is placed above ground on a slope and is not anchored correctly or has too much flow resistance, you will likely see a coupling failure in the future. By planning ahead, you can minimize the number of couplings by ordering longer lengths of pipe. Pipe Anchors Pipe anchors should be used for pipes on steep slopes. Pipe bends should be adequately supported.
Water flowing downhill can place tremendous forces on pipe connections and bends.
Do not underestimate the need to resist these forces by anchoring and supporting the pipe. Pipe anchors are not purchased but are built in place. Pipes should be anchored above grade as well as below grade. The gravel provides a uniform bedding for drain pipes to create a consistent pipe slope and provide a free draining material adjacent to perforated pipes. Water moves through the spaces between the gravel before entering a pipe or other means of conveyance.