Abstract: A valve assembly having a tubular valve body defining therein a main supply passage, which tubular valve body has an inlet opening at one end thereof, and an outlet opening adjacent the other end thereof in perpendicular relationship to the main supply passage. A sleevelike socket member is seated within the main supply passage in the vicinity of the outlet opening. The sleeve member has a communication opening through the sidewall thereof in alignment with the outlet opening, which communication opening confines therein an elastomeric seal ring for sealingly engaging the interior wall of the tubular body around the outlet opening. A shaftlike valve member is rotatably seated within the sleeve member and has an L-shaped flow passage which extends axially from the upstream end and then outwardly through the cylindrical sidewall for alignment with the communication opening when the valve member is rotated into its open position.