An environmentally safe underground piping system which employes a inner flexible fluid supply piping system contained within an outer non-flexible containment piping system which interconnects a series of surface access chambers. Both the flexible supply and and non-flexible containment piping systems are interconnected by a series of directional fittings and couplings. The containment system may be installed, integrity tested, inspected and backfilled, prior to installation of the supply piping system which allows for a faster and more economical installation.