Legionnaire’s disease prevention for property & community managers & HOAs

Jason Van Steenwyk
Jason Van Steenwyk | 7 min. read

Published on August 27, 2015

If condominium boards of directors and property/community managers haven’t thought about Legionnaire’s disease prevention and protocols, it’s time to get serious. A Legionnaire’s disease outbreak in New York City this summer killed over a dozen people and sickened at least 127.

The legionella bacteria that causes the disease flourish in warm stagnant water in cooling and reservoir tanks, hot tubs, Jacuzzis, spas, shower facilities, and humidifiers. Legionella has also been known to contaminate central air conditioning units and vents. The bacteria spreads quickly in water or moist air between 77 and 117 degrees Fahrenheit (25 and 42 degrees Celsius, respectively).

According to the Occupational Safety and Health Administration (OSHA), Legionnaire’s disease affects as many as 10,000 to 50,000 people every year. While a few outbreaks, such as the recent New York City one, grab headlines, small cases of one to a handful of people are common but frequently don’t make the news. Nevertheless, even a single incident can potentially expose landlords and property managers to significant liability. Those stricken with the disease can easily generate medical bills in the six-figure range, thanks to lengthy hospital stays, even when the case is not fatal.

Legionnaire’s disease has long been recognized as a significant threat to hospital patients and staff as well as guests and employees in the hotel and hospitality industry, but it’s a threat anywhere people share an environment with warm, stagnant water or moist air.

The disease is often lethal, with a mortality rate in any given outbreak ranging from 5 percent to 30 percent. Epidemiologists peg the fatality rate among hospital outbreaks at 28 percent, with the most common source of infection being unsanitized drinking water from taps and water fountains.

Thus far, none of those infected can trace their infection back to a residential facility, but property managers and condominium boards of directors still retain responsibility for the common area facilities under their control. Prevention of Legionnaire’s disease requires being diligent and proactive.

But don’t look to OSHA for guidance. They have no specific standards for Legionnaire’s disease prevention. Instead, property managers should combine the efforts of the heat, ventilation, and air conditioning (HVAC) industry and hospital industry to create a Legionnaire’s disease prevention protocol that works specifically for their own properties.

This article covers areas of concern for residential property managers, community managers, HOAs, and condominium associations, including preventive methods, most of which involve water sanitation.

Hot tubs

It’s very easy for hot tubs to become infected if the property managers and boards neglect some very basic care and maintenance. In one case, an outbreak of the disease was traced back to a display hot tub in a retail store! Contract with a pool/hot tub maintenance company. Or invest time in training your maintenance staff on how to test and prevent Legionnaire’s disease in these critical environments.

  • Periodically have your hot tub or jacuzzi inspected by health officials.
  • Check disinfectant and pH levels twice a day. More often when the hot tub is in frequent use. You can easily buy pool test strips at any home improvement store or pool supply store.
  • The Center for Disease Control recommends you check for free chlorine (2-4 ppm), or bromine (4-6 ppm). The pH level should be between 7.2 and 7.8.)
  • Clean the pool and hot tub periodically. Be sure to scrub the biofilm/algae layer off the sides.
  • Replace the hot tub filter in accordance with manufacturer’s specifications.
  • If your hot tub is contaminated with Legionnaire’s bacteria, follow the steps on this worksheet.


Does your facility have a pool? It’s the board’s responsibility to maintain it, or delegate that function to a property manager. Does the maintenance staff have the proper training to keep your pool safe and sanitary? Consider sending one or more members of the maintenance staff to a certified pool operator training course.

If that’s not practical, ask your property manager if any of their staff has any pool or aquatic sanitation training and experience. If not, you may need to explore outsourcing this function to a professional pool servicing company.

Water heaters

Water in water heaters should be maintained at 140 degrees, Fahrenheit (60 degrees, Celsius), to ensure the water is free of bacteria. Any temperatures lower than that give legionella a chance to build up.

Solar systems

The risk if Legionnaire’s infection is increased when solar power is insufficient to adequately heat water in storage tanks and water heaters. For example, a tank that is too large for the solar system could become a breeding ground for bacteria, if the system can’t heat the water past the point that kills the legionella bacteria. The risk is higher where water is stored between 25 and 45 degrees Centigrade.

Water Lines

Flush rarely used water lines regularly — especially if water tests positive for high concentrations of legionella bacteria. Residential water systems can be flushed using protocols similar to those adopted by hospitals: Increase the hot water heater temperature to the maximum (at least 140 degrees) and flush the whole system with hot water for 20-30 minutes, according to information from the American Society of Heating, Refrigerating and Air Conditioning Engineers.

Additionally, even if there’s been no positive test result, the U.K. Residential Landlord’s Association recommends running the hot water taps full blast for at least 2 minutes to kill any accumulated bacteria if the dwelling has been unused for a significant period of time, or prior to turning the unit over to a new tenant. They also recommend encouraging tenants to clean, disinfect and descale showerheads regularly.

Cooling tower legionella

Cooling towers are especially hazardous for Legionnaire’s disease because they are essentially open-air pools of warm standing water. They are ideal environments for legionella to flourish. True, the water in these towers is not drinkable, but it doesn’t have to be for the disease to spread. Water in cooling towers evaporates, and individuals can breathe in the contaminated water vapor, leading to infection. If your property has a cooling tower, you need to be extra vigilant about having it professionally cleaned on a regular basis.

Cooling towers and condensers should receive thorough cleaning and sanitation twice a year or more. Have HVAC professionals remove all algae and biofilm and treat all surfaces with a disinfectant agent/biocide, and replace any parts that have corroded.

Wherever there are groups of people in close proximity and water that doesn’t go through a sanitation process before consumption, Legionnaire’s and other water-borne diseases are a very real threat. As a property manager, do yourself and your tenants a favor: Stay on top of water sanitation and the maintenance of your hot tubs, pools, and systems that contain or transport water to prevent a potentially life- or health-threatening outbreak.

What are your policies for preventing disease at your properties or in your communities? Do you manage your sanitation and maintenance processes yourself or outsource the job to a qualified vendor? Share your experiences and knowledge in the comment section below.

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Jason Van Steenwyk

Jason is a freelance writer and editor, as well as an avid fiddler. His articles have been published in a number of real estate publications including Wealth and Retirement Planner and Bankrate.com. He lives in Fort Lauderdale, FL with his cat, Sasha, and an unknown number of musical instruments.

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