Abstract: A compression seal for conduits that pass through watertight barriers, such as containment sumps for underground gasoline pumping systems, involving two annular seals of compressible material, a first in the barrier aperture and a second on the conduit, connected by a flexible conical section which provides compliance to both axial and angular movement of the conduit. An inner supporting ring of rigid material is used to force and maintain the first seal in compression sealing relationship, irrespective of roundness variations, within the aperture, and a screw tightened band is used to retain the second seal in a compression sealing relationship about the conduit.