Oxygenators for cardiopulmonary bypass require water flow for their integral heat exchanger. Heater-cooler units are nearly universally used for this requirement. Heater-cooler units pose the risk of aerosolized infection. The Centers for Disease Control and Prevention recommended discontinuing use of Stöckert 3T heater-cooler units (LivaNova PLC, London, United Kingdom) in October 2016 because of this risk. We aimed to reduce the risk of aerosolized infection posed by heater-cooler units by eliminating those devices from our operating rooms.The cardiac surgery division collaborated with in-house specialties to engineer a novel wall water system. The design called for service to 4 operating rooms with the actual water mixing valve in an operating room closet. Remote temperature control was mounted next to the heart-lung machine. Primary safety systems built into the water system include 5 μm filtration, pressure regulating and relief valves, flow quantifiers, limits to the hot and chilled input temperatures, and a novel bridge near the heart-lung machine that allows the perfusionist to test the system before patient use and to quickly disconnect the patient in case of system malfunction. In addition, all water line connections can be made with the tubing drained and never under pressure.This novel wall water system has successfully provided heat exchanger water flow on 625 patients undergoing congenital heart surgery requiring cardiopulmonary bypass during its first 9 months of use.Wall water systems are an option for oxygenator heat exchangers that allow for improved heat exchange performance while reducing the risk of heater-cooler unit-associated infection during cardiac surgery.