https://sites.google.com/view/altavax/blog-1

Legionella testing is a standard aspect of managing, monitoring, and assessing risk in any facility: it verifies status and monitors the direct impact that controls, corrective action, or events outside of permissible range have on Legionella levels. Regular Legionella testing mitigates the potential health and legal concerns associated with disregarding this aspect of Legionella risk assessment.