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Reopening Facilities After Prolonged Shutdown or Reduced Operations for Facilities Off Cornell's Water System


The purpose of this standard operating procedure is to help unit facility managers of Cornell owned facilities flush water distribution systems that have been dormant during the COVID-19 pandemic. Flushing the building’s potable water system(s) and equipment will remove stagnant and potentially contaminated water from its system.


This procedure is in addition to all other operational requirements, COVID-19 related procedures, and public health authority requirements.

  1. Consult with your water purveyor (public or private utility service) to determine if guidance exists for reopening buildings after prolonged shutdown or reduced operation.
  2. If your water purveyor does not have guidance or your facility is supplied potable water via a dedicated well system, complete the following steps.
    1. If your facility is on a dedicated well, inspect the source of water for potential sources of contamination, e.g. well cap/tank lid is in place preventing any contamination from entering the system. 
    2. If your facility’s potable water is purveyed by a public or private utility service and you choose to perform quantitative measurements on system’s chlorine residuals outlined in bullet 2.c.ii., start by flushing the water entering the facility near the meter or at the first tap and ensure the water has detectable disinfectant (chlorine residuals) levels prior to beginning entire building flushing.
      • If the test does not yield detectable disinfectant levels, contact your water purveyor.
    3. Flush the internal plumbing of the building, which may need to occur in segments (e.g., floors or individual rooms) due to facility size and water pressure. The purpose of building flushing is to replace all water inside building piping with fresh water.
      • i. Flush hot and cold water through all points of use, e.g. showers, sink faucets, drinking fountains, plumbed dispensers, etc.
        • Begin with the highest and furthest hot/cold fixtures.  If necessary, consult facility plumbing diagrams/layout.
        • Flush cold-water fixtures until the water becomes coldest, a minimum of fifteen (15) minutes.
        • Flush hot water fixtures till the water reaches maximum temperature, a minimum of fifteen (15) minutes.
          • To avoid bacteria and mold growth set all hot water heaters to 120°-140° Fahrenheit. Follow the manufacturer's recommendations for water heater maintenance after a prolonged period of disuse. Ensure that all maintenance activities are carried out according to the manufacturer’s instructions.
      • ii. Quantitative Method: Facilities connected to public or private utility service may implement a process to test for chlorine residuals using a Free Chlorine Color Wheel, or Pocket Colorimeter II, as opposed to time method outlined above.
    4. Eye wash stations shall be flushed and inspected per the weekly inspection requirements.
  1. Below are tasks to be performed post-flush of the facility’s potable water system.

    1. Post-Flush Inspect and maintain any water treatment systems per manufacturer’s guidelines, e.g. filters, water softeners, etc.   
    2. Post-Flush replace all in-line water filters and then develop a changing schedule consistent with the manufacturer’s guidance.
    3. Post-Flush ice machine(s) and other similar devices used for human consumption should be cleaned, sanitized, and maintained per the manufacturer’s instructions.
    4. Notify Susan Hartman (slh8) or Laurrie Coffin (ljc8) of your facility’s successful completion of the above procedure.

                             i.  If your facility has continued to remain occupied, please communicate that as well.


Employee Pre-Work Decision Tree

  1. Identify the source of water for the building.

  2. Review plumbing diagrams/layout within the facility, if necessary.
  3. Notify building occupants the status of water systems and flushing operations.
  4. Document completion and any testing results, if applicable.