Water needs to flow through the pipes of buildings to avoid getting stagnant. Water held unused in building pipes while businesses or activities are shut down, or have unused floors or sections, can lead to other problems if not taken into consideration when reopening.  

Conditions may develop increasing the risk for the growth and spread of waterborne bacteria, such as Legionella or biofilm, in the building piping. Corrosion of metal in the piping of the building may occur because ph levels can fall as stagnant water sits in plumbing. Disinfectant in the water, such as chlorine, will likely dissipate or become undetectable.  

Actions are necessary to ensure the water in the building is safe as well as taste and odor free before resumption of normal water use. The Center for Disease Control and Prevention (CDC) recommends 8 Steps to take before your business or building reopens:

1. Develop a comprehensive water management program for your water infrastructure and all devices within your building that use water;
2. Ensure your water heater is properly maintained and the temperature is correctly set;
3. Flush hot and cold water through all points of use;
4. Clean all decorative water features, such as fountains, following manufacture guidelines for cleaning
5. Ensure hot tubs/spas are safe for use;
6. Ensure cooling towers are clean and well-maintained according to manufacturers specifications;
7. Ensure safety equipment including fire sprinkler systems, eye wash stations, and safety showers are clean and well-maintained according to manufacturers specifications;
8. Follow your water management program, document activities, and promptly intervene when problems arise.

The CDC has very detailed information on reactivating plumbing systems after dormant conditions on its website at:  https://www.cdc.gov/coronavirus/2019-ncov/php/building-water-system.html