My last two columns discussed both chemical and non-chemical additives or technologies that I treat as “must consider” for plumbing engineers in their design practices to reduce the risk of Legionella bacteria developing in the domestic water system. As I mentioned, these topics might not be a code minimum requirement, but as an engineering community, we have a responsibility to uphold the health and safety of the public. Therefore, we should discuss these technologies with our clients for many different building types we come across in our design.