4 The record articles

Ready to Reopen? Don’t Forget to Check Your Water Systems!

Posted: June 3rd, 2020

Authors: Sharon S. 
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There are many articles out there about preparing stagnant buildings for reopening, and they contain valuable information.  One topic that’s commonly discussed is the hazard with uncirculated or untreated water, particularly the potential for legionella growth.



As you prepare to safely re-enter buildings, these reminders can help you get started:

  • Coordinate plans with your Environmental, Health, and Safety personnel and your water treatment vendor/chemical supplier.
    • Key considerations – safety of personnel sampling water, evaluating hazards of additional chemicals required to treat stagnant water, and maintaining documentation of steps taken to prepare for reopening.
  • Identify equipment and water connections where legionella can grow.
    • This can include water distribution systems, hot water systems, closed-loop systems such as cooling towers and boilers, and water collection points like HVAC drainage pans.
  • To ready your municipal drinking water, flush the system until you are satisfied with the level of residual chlorine at the furthest tap in the system.
    • For added comfort, collect water samples and send them to a lab to test for legionella.
  • To ready your well-sourced water, flush the system, ensure an adequate chemical supply to disinfect/treat the water, and test water samples for residual chlorine, legionella, and other waterborne bacteria such as coli.
  • To ready your closed-loop systems, coordinate with your water treatment vendor/chemical supplier to treat the water.
    • This may require an increased dosage of chemical to mitigate the impacts of stagnation.
    • Testing of water samples may be required.
  • Inspect and drain water collection points of excess moisture prior to opening the building.
  • If new chemicals are used for water treatment during the building re-start, evaluate those under your “Chemical Approval” policy/procedure.
  • Recommendations for after reopening:
    • Continue routine legionella testing.
    • Compile a procedure for future events based upon steps taken to prepare for reopening, including information about vendors, chemicals/dosages, analyses performed/lab used, and recommendations for improvements based upon lessons learned.

If you’re looking to establish a water management program, the Virginia Department of Health provides a helpful summary (https://www.vdh.virginia.gov/drinking-water/legionella-information-for-consumers-and-building-owners/) and refers to additional resources from the Centers for Disease Control, including this toolkit: https://www.cdc.gov/legionella/downloads/toolkit.pdf

For support with programs and procedures for your building’s water systems, or other EHS consulting needs, please contact Sharon Sadler (ssadler@all4inc.com or 571.392.2595).


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