Legionella in Water Systems
September 2018: By Susan Browne Rosenberg, CIH, CIEC (expired 02/2020), CHMM
President, Desert Cities Indoor Air, LLC
760-902-2545 www.dcindoorair.com
Legionella has been the focus of several local news reports this year. According to a story posted August 16, 2018 on the KESQ website¹, “The pool at the Four Seasons, 55+ community in Palm Springs, was supposed to be back open this month after testing positive for Legionnaires’ Disease in June. However, the pool will now remain closed after testing positive for Legionnaires’ again.” The key word here is “again.” The story reveals that the pool was closed for months during this past summer in response to a report of the disease in two residents and subsequent positive test results from the pool water.
So what is Legionella? Legionella is a bacteria with over 60 different species. They live naturally in rivers and fresh water lakes. The optimum temperature range where the bacteria thrives is 95 to 115°F. Below 68°F the bacteria is dormant. Exposure to temperatures over 158°F kills the bacteria immediately. Hot water heated to at least 140°F (as in hot water heaters) kills 90% of the bacteria.
Bacteria growing in the floating white biomass of a condensate pan of an air-conditioning system.
The symptoms of Legionnaire’s Disease are similar to flu-like symptoms. In the elderly (people over 65 years old), smokers and people with COPD, Diabetes or immunocompromised systems, the risk of exposure is much higher. Senior living housing units and nursing homes are particularly set up for concern. Exposure occurs when an individual is exposed to aerosolized droplets such as from showerheads, bubbling hot tubs and indoor fountains.
Reported cases are up four-fold since 2014. The Centers for Disease Control contributes this to several factors including better reporting, an aging population and increasing temperatures from climate change. The CDC also stated that they believe that 9 in 10 cases “could have been prevented.”
Does your community (HOA) maintenance plan include a Water Management System? These plans are now required in New York City in multiunit residential buildings over ten stories high with a centralized water heater system. In our valley the only buildings potentially meeting this standard are the few high rise hotels.
We do have a lot of pools and hot tubs here that need regularly scheduled maintenance and testing. The Riverside County Department of Environmental Health has an information bulletin on Disinfection of Hot Tubs contaminated with Legionella. But before you reach that point, please make sure that your community hot tubs are following guidelines for “Operating Public Hot Tubs” by following pH and chlorine levels and other measures for Hot Tub safety. One of the points of order for HOA Board Discussion should include excluding children less than five years old from using hot tubs.²
The November December 2015 issue of Common Ground published by CAI National had an article on Legionella after an outbreak in New York that claimed 12 lives and sickened more than 100 from a hotel cooling water tower. The article offered four Prevention points to keep your community safe:
- Identify and assess risks.
- Review regulations.
- Create a plan.
- Monitor compliance.
Testing the water for Legionella is easy, but must follow a strict protocol for collection and submission to a certified laboratory. Water samples must be processed the day after collection, so timing is critical. Desert Cities Indoor Air uses only CDC Elite Certified labs for this analysis. Swabs of filters, showerheads or other surfaces where there is a biofilm can also help locate and identify areas of concern. Samples should only be collected as part of a plan with maintenance staff. If someone has self-identified a case of Legionnaire’s Disease, the local county public health department should be notified immediately. County staff may want to be involved with a sampling plan and may want to collect their own samples.
In summary, Legionnaire’s Disease is a serious, but preventable disease. See the attached pdf on hot tub maintenance for more information.
² https://www.cdc.gov/healthywater/pdf/swimming/resources/operating-public-hot-tubs-factsheet.pdf