Abstract: A drain closure valve is disclosed having a wide mouth body member including a substantially cylindrical body annular wall portion with a fluid passageway therethrough and having a cap for sealing engagement therewith. The cap includes a substantially cylindrical cap annular wall portion and a bottom wall portion, a stepped annular ridge which defines a ridge upper annular wall portion and a ridge lower annular wall portion joined by a ridged upper horizontal wall portion, and threads affixed to the annular wall portions of the cap and the body member allowing the cap to threadably engage the body member. The seal comprises a protrusion extending outwardly from the cap annular wall portion which sealingly engages against the lumen of the body annular wall portion.