Solid Science Practical Solutions


Legionella Contamination a Greater Risk in Warm Summer Weather

Legionella contamination can be a serious issue after a building shutdown.  These bacteria are responsible for causing Legionnaire’s Disease, a serious and common respiratory illness.  Temporary shutdown of buildings can result in stagnant water in the building’s plumbing system which increases the risk for growth and spread of Legionella and other biofilm-associated bacteria.


What You Can Do:


  • Aggressively flush water outlets for at least 30 minutes daily for 1-2 weeks with an emphasis on less frequently used outlets and those with aerators, shower heads, spray faucets, shower heads, decorative fountains, etc.
  • Follow up with water testing for Legionella bacteria to determine if you have a problem.
  • Review building plumbing plans and eliminate dead zones where water can stagnate.
  • Be sure that hot water remains above 125°F throughout the distribution system.
  • Have water towers, tanks, etc. regularly cleaned, sanitized and tested.
  • Regularly remove and sanitize (or replace) aerators, showerheads, ice machines, and other outlets associated with aerosolized or stagnant water.
  • Have HVAC systems regularly inspected for evidence of stagnant water, corrosion, and mold which can indicate a high risk for Legionella growth.
  • Most importantly for the long term establish a comprehensive “Water Management Program” for your building(s). 


How GSE Can Help:


  1. Design and conduct building(s) survey(s) to identify possible high risk conditions.
  2. Conduct a water testing program for high risk locations.  Test results deliver critical data to guide decisions and provide documentation of effective remedial efforts.
  3. Interpret lab test results and develop site-specific remedial action plans if needed.


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