Abstract: A lockable valve cover has a housing with an open end and a pair of opposing slots on opposite sides of the housing extending from the open end for engaging over spaced locations on a pipe on opposite sides of a valve over which the housing is placed, the pipe extending in a first direction through the slots. A pair of openings on opposite sides of the housing are aligned in a second direction perpendicular to the first direction with a first opening being larger than a second opening, and a locking plate having a reduced width tongue engages across the housing through the openings, with the tongue projecting through the second opening. A padlock engages a hole in the tongue to lock the housing in place.