The game was poised on a knife's edge at half time at 13-12 before Wasps opened up to claim five league points.
Wasps opened the scoring with two well struck penalty goals by Alex Hodgkinson. Letchworth weathered the further pressure and then gradually worked their way into Wasps' territory. Their stand-off managed to break a double-team tackle and offloaded to his outside centre, who rounded the scramble defence and scored in the corner.
Yoni Dennis restored Wasps's lead with a short range pick and drive. Letchworth ended the half with a sweeping move which earned several penalties on Wasps' 5 metre line. Eventually pressure told, and the teams turned round within a point of each other.
Wasps settled things down in the second half and scored four unanswered tries through Cammy Mulcaire, Yoni Dennis, Roscoe Sun and Alex Hodgkinson as the visitors ran out of steam.