Water mist systems (WMS) are commonly used to cool public places, but they can be colonized by opportunistic premise plumbing pathogens (OPPPs) that cause infections in people with predisposing conditions. Adequate knowledge of health risks associated with these systems is important to avoid exposing people to OPPPs. In 2019, we conducted a questionnaire survey of 10 business owners who used WMS and 22 environmental health officers (EHOs) to assess their knowledge about the health risks of WMS. A majority of the owners (60%) and EHOs (77%) were not aware of the health risks. Only 50% of these business owners regularly maintained their systems, 60% used maintenance and cleaning schedules, and a high percentage (90%) had no training in the operation of the WMS. All EHOs surveyed reported that the installation and operation of WMS are unregulated.