In response to the ongoing COVID-19 pandemic, the US Centers for Disease Control (CDC) published updated guidance on addressing the potential for growth of Legionella in building water systems after a prolonged shutdown. The Guidance presents 8 steps to take before “…your business or building reopens.”
Link to CDC Guidance:
https://www.cdc.gov/coronavirus/2019-ncov/php/building-water-system.html
CDC introduction to the Guidance (copied from the website):
“Ensure the safety of your building water system and devices after a prolonged shutdown”
“Stagnant, or standing water can cause conditions that increase the risk for growth and spread of Legionella and other biofilm-associated bacteria. When water is stagnant, hot water temperatures can decrease to the Legionella growth range (77–108°F, 25–42°C). Stagnant water can also lead to low or undetectable levels of disinfectant, such as chlorine. Ensure that your water system is safe to use after a prolonged shutdown to minimize the risk of Legionnaires’ disease and other diseases associated with water.”
