Fall 2020 Water Testing
Water Testing > Fall 2020 Water Testing
This fall, as part of ongoing work to ensure Ann Arbor Public Schools buildings are well-prepared for the return to in-person learning, we have been focused on ensuring water quality. In addition to installing hydration stations across AAPS schools last year and installing filters in all drinking water locations, we continue flushing the plumbing three times a week, removing drinking fountain bubblers and replacing all drinking water filters. Recognizing additional risks to the water system in older, unoccupied buildings, we have also proactively expanded our existing water testing program to include E Coli and Legionella in addition to our ongoing Lead in Drinking Water Testing Program.
While testing currently continues, results of preliminary testing conducted by Arch Environmental Group have shown elevated levels of Legionella in a few locations across the AAPS. These locations have been taken out of service until mitigation strategies are complete and follow-up testing has been completed. Answers to Frequently Asked Questions about Legionella are included below.
In coordination with the Washtenaw County Health Department and the Michigan Department of Health and Human Services, our mitigation program includes:
- Add a chlorine solution that kills the Legionella bacteria and run through every outlet
- Flush the water system again to ensure any excess chlorine is removed
- Arch Environmental Group will conduct additional testing
When testing and necessary mitigation measures are completed across AAPS buildings, we will publicly share all testing results, locations and the steps that have been taken to correct the issue.
In addition to these mitigation strategies, the AAPS continues to work proactively on water issues to enhance the district water safety plan.
Legionella Frequently Asked Questions
What is Legionella?
Legionella or formally known as Legionellosis, is a collection of infections caused by Legionella pneumophila and related to Legionella bacteria found in water systems.
Where are Legionella bacteria found?
Water is the major natural reservoir for Legionella bacteria found worldwide in natural and artificial water environments such as cooling towers, water systems in hotels, homes, ships and factories; respiratory therapy equipment, fountains, misting machines and spa pools. Legionellae is also found in natural water environments such as water on plants in rainforests, groundwaters, soil and seawater (WHO).
Typically, Legionella bacteria is not found in drinking water fountains that are limited to cold water flows. Cold water sourced drinking water fountains do not have heated water (77 °F and 108 °F) flowing through it. Additionally, Legionella does not present an ingestion risk but rather an inhalation risk.
How does Legionella develop, especially during the COVID Pandemic?
When buildings, including schools, are not in use, water systems will have low to no flow through their piping systems and storage tanks. The increased time between when water enters the system and when it is consumed or discarded can cause areas of stagnant water. This has a negative impact on water quality, such as changes in water color and taste, increased corrosion processes and the growth and formation of biofilms, which may lead to Legionella bacteria. The longer the standing time of the water in the building system, the longer bacteria and microorganisms have to proliferate and concentrate that can generate infections and health problems for users of the water system (NSF)
What factors increase the likelihood of the presence of Legionella?
- The presence of nutrients in both the source water and in the material of the water delivery system, such as the pipes.
- Scale and corrosion in the water system.
- Warm water temperatures.
- Stagnation or low flow of water distribution systems such as through pipes or water held in storage tanks.
What are the impacts of Legionella?
The impacts of Legionellosis bacteria vary from a mild illness (Pontiac fever) to a potentially fatal form of pneumonia (Legionnaires’ disease). While these bacteria can affect anyone, they principally affect those who are susceptible due to age, illness, immunosuppression or other risk factors such as smoking. Not everyone exposed to Legionella will develop symptoms.
How is Legionella transmitted?
An infected source, such as a fountain, can disseminate sprays or droplets of water containing Legionella bacteria, commonly referred to as aerosols. When this occurs, most or all of the water in the droplet evaporates quickly, leaving airborne particulate matter that is small enough to be inhaled deeply and enter the respiratory airways to cause Legionellosis. (Fitzgeorge et al.,1983). There is no evidence of person-to-person transmission of either Legionnaires’ disease or Pontiac fever (WHO, 2004).
What measures can be put in place to control the likelihood of Legionella forming in water systems?
- Control nutrient levels in the water system ensuring chemical additives are used to control scaling, corrosion and microorganism.
- Prevention of low flow and stagnation by flushing the water systems frequently.
- Temperature control – keeping water temperature outside the ideal range for legionella formation by avoiding temperatures between 77 °F and 108 °F to prevent legionella colonization.
- The World Health Organization (WHO) – Legionella and the prevention of Legionellosis https://www.who.int/water_sanitation_health/emerging/legionella.pdf