The COVID-19 pandemic has changed how water is used in commercial or industrial buildings that have closed or greatly reduced operations. Letting water sit in pipes for long periods of time can create water quality problems in these buildings. Buildings and businesses that have been closed or have significantly reduced water use should flush their internal pipes to replace the stagnant water with fresh water prior to occupants returning.
Seattle Public Utilities suggests following the recommendations from WA Department of Health’s “COVID-19 Guidance for Legionella and Building Water System Closures“. Additional information from WA DOH on building chlorination is available: “Shock Chlorination Guidance for Building Water Systems.”