There is a growing body of literature on infection with nontuberculous mycobacteria (NTM) associated with heater chiller units in the cardiac surgery population. We report a pediatric case undergoing reoperation for early right ventricle-to-pulmonary artery conduit stenosis. A successful outcome was achieved following excision of the infected conduit and six-week antibiotic treatment. To our knowledge, there is only one other pediatric cardiac case reported in the literature. Similar to the recently reported cases of infection associated with Mycobacterium chimaera in predominately adult patients after cardiac bypass surgery, we hypothesize that water-containing devices such as the heater chiller unit and water blanket acted as a reservoir for other NTM. With increasing awareness of NTM, we analyzed the 2015-2016 culture data on our fleet of eight heater chiller units. We identified an association between persistent positive cultures and the connection of a water mattress to the heater chiller unit circuit. This led us to abandoning the use of the mattress in pediatric cardiac surgery.