During the COVID-19 pandemic, many buildings are being vacated to accommodate social distancing. The lack of water system use in these empty buildings may create stagnant areas and environments for microbial and pathogenic growth, such as Legionella.
To maintain the quality of building water systems, there are a number of resources available that address concerns and actions to take, such as a regular flushing program.
The best plan of action is to have a Water Management Program that addresses building water quality, including instances when building water systems are shut down or inactive. Note that the guidance provided below is general, and all buildings and systems are different and have unique needs.
Environmental Protection Agency (EPA): Maintaining or Restoring Water Quality with No or Low Use and Checklist: Restoring Water Quality in Buildings for Reopening
Coronavirus Building Flushing Guidance from the Environmental Science, Policy & Research Institute
Centers for Disease and Prevention (CDC): Guidance for Building Water Systems: Ensure the Safety of Your Building Water System and Devices After a Prolonged Shutdown.
Purdue University Center for Plumbing Safety FAQ and study on water quality in low-occupancy and shutdown buildings.
ASHRAE FAQs, including technical resources for HVAC maintenance.