Showers and sinks with aerators are possibly the most common ways humans come in contact with this deadly bacteria. Hotels, residential buildings, hospitals and educational facilities maintain hot water recirculation systems. These systems operate at the perfect temperature to breed bacteria especially legionella. Most of the population come in contact with a sink or a shower in contrast most individuals will never come in contact with a cooling tower, water droplets (which need to be inhaled) will never make into the building personnel’s lungs.
These systems will need to have special treatment systems, special fixtures, elevated temperature requirements far past scalding, and/or instantaneous hot water conditions to combat legionella. Rest assured, if any system should maintain requirements or legislation, it would be this system.
At this time, no laws exist with regard to this type of system yet, because of recent outbreaks in buildings which do not maintain cooling towers and testing points directly to this system being the source of contamination be assured that this is currently being looked at and will eventually be regulated