Hospital wastewater is an increasingly recognized reservoir for resistant Gram-negative organisms. Factors involved in establishment and persistence of Klebsiella pneumoniae carbapenemase-producing organisms (KPCO) in hospital wastewater plumbing are unclear.</p><p>This study was conducted at a hospital with endemic KPCO linked to wastewater reservoirs and robust patient perirectal screening for silent KPCO carriage. Over five months, both rooms occupied and not occupied by KPCO-positive patients were sampled at three wastewater sites. Risk factors for KPCO positivity were assessed using logistic regression.</p><p>KPCO-positive patient exposure was associated with increased risk of environmental positivity for the room and toilet/hopper.