COVID-19 “stay-at-home” orders have reduced water usage in facilities across the globe as buildings are shutdown or operated with low occupancy. The resulting stagnation in building water system equipment, piping, and fixtures can increase the risk for Legionella and other biofilm associated bacteria to grow, contribute to unsafe levels of lead and copper in potable water systems, and cause other serious problems.
This article was developed to provide building owners and operators with an overview of strategies that can be taken during shutdown and when buildings reopen to help address the Legionella risks associated with stagnation. However, due to the complexity of building water systems, the impact of operational and maintenance practices, and the universal nature of Legionella bacteria, no plan, program, or maintenance measures can guarantee the absence of Legionella or transmission of Legionnaires’ disease.