Quick view Various1 PVC 6" Utility Backwater Valve (S x S) Compare $148.62 A Backwater Valve is designed to function as a check valve in a drainage pipe to prevent flowing liquid, such as sewage, from reversing its direction. There are other applications for Backwater Valves, such as multi-level pond balancing for Aquascape... Add to Cart Add to Cart Add to Wish List Add to My Wish List Create New Wish List