An exemplary cover for a conduit body integrates a lid with a gasket. The gasket is a closed loop with an upper rim portion and a lower rim portion forming an inner groove therebetween. The lid includes a hump surrounded by a border, and the border is positioned within the inner groove to secure the lid and the gasket together. The border of the lid has a slight convexity with respect to the bottom side of the lid, providing the lid with a slight curvature toward the conduit body. As a result, the lid bows downward between two fastening points at opposing ends of the lid. The gasket preferably includes a ridge protruding down from the lower rim portion. This ridge also faces the conduit body on which the cover is removably secured.