12 More years, 12 more years
KEK
That is a very astute observation.
https://www.osha.gov/SLTC/legionnairesdisease/hazards.html>>10786718
What happens when you flush a toilet/urinal, turn on a tap/shower - instant atomisation. When water has been standing for a period of time (which varies depending on certain other conditions, source etc.) .
If a building has been closed up for a few weeks, precautions shouldbe taken. One site says shower heads should be cleaned and disinfected every three months - that's likely for a well used shower.
I worked somewhere when younger and the maintenance guys did routine Legionella cleaning WEEKLY (tanks, water cisterns etc.), and that was in a busy, staffed location.