The HydroVent manhole cover uses LiftMate ball-and-socket hinge system technology coupled with a heavy-duty latching mechanism. The manhole cover provides surge relief at the installation location during events in which the sewer system becomes surcharged. The product is made in the U.S., ensuring acceptability with federally funded projects. No dead lifting is required to close the cover. The hinge easily disengages for complete lid removal, with no tools required. The cover is traffic rated and exceeds the 40,000-lb proof loading requirements of AASHTO-M-306-07.