Preventing And Managing Legionella In Potable Water Systems

Alex Gowgiel Blog

By: Alex Gowgiel, PE, CWT
HOH Water Safety Compliance Specialist

world vision 6kLast week, the team at HOH participated in the World Vision Global 6K for Water. The event supports their mission to bring clean drinking water to communities in need. I bring that up because while preventing Legionella in our potable water systems may seem like a daunting task, it’s relatively easy when compared to solving the world water crisis – more on that later in the article.

For the past ten years, I’ve worked with HOH to help deliver on our mission to ‘Make a Lasting Impact With Water’ – first as the Equipment Specialist, then as a Water Quality Engineer, and now in my role as a Water Safety Compliance Specialist. During my time at HOH, there has been an increased focus on Legionella awareness, detection, and prevention.

Legionella is a high-profile, headline-grabbing bacteria, and for good reason. If a Legionnaires’ Disease outbreak occurs, especially when fatalities are reported, it’s extremely damaging (and expensive) to a business or organization.

I’m passionate about educating our customers about Legionella. In fact, I felt so passionately about it that I became certified by the ASSE as a Legionella expert and now assist the HOH team in our efforts to raise awareness and help our customers maintain safe water systems.

How Big of A Problem is Legionella In Potable Water Systems?

Legionella pneumophila, commonly called Legionella, can grow in many types of residential, commercial, and industrial water systems. When people inhale or aspirate droplets of Legionella, they can get a serious lung infection known as Legionnaires’ disease or an infection known as Pontiac Fever. Legionnaires’ disease has symptoms similar to pneumonia and can be fatal, while Pontiac Fever is a milder infection that typically gets better without the need for medical intervention.

Small amounts of Legionella bacteria can grow in untreated or stagnant systems and lead to an outbreak of Legionnaires’ disease. Legionella can be found in both hot and cold water and both domestic and process water. It can find its way into your facility through various sources including your municipal water supply or ambient air through small droplets.

You may find it interesting to know that not all species of Legionella are harmful to humans. Some variants do not affect us and are non-pathogenic. While the presence of these non-pathogenic species does not carry the same weight as the presence of Legionella pneumophila, it does indicate the system has the environment for the bacteria to live.

That being said, it’s important to be aware of the risks of Legionella and to be compliant with industry standards such as ASHRAE 188.

This is especially critical for the healthcare industry as the CMS (Centers for Medicare and Medicaid Services) controls federal funding for these facilities and can withhold that funding if a facility is found non-compliant with ASHRAE 188.

ASHRAE 188 requires that healthcare facilities have water management policies and procedures in place to reduce the risk of Legionella and other opportunistic pathogens in their building water systems. If a healthcare facility does not have the appropriate measures in place, they risk a non-compliance citation from CMS.

There has been a dramatic increase over the past twenty years of reported Legionnaires’ Disease cases. According to the Centers for Disease Control and Prevention (CDC), the rate of reported Legionnaires’ Disease cases has increased by nearly 900% since 2000. This may be due to the fact that there is more awareness and more testing being done. The rise in cases may also be due to increased susceptibility of the population, increased Legionella in the environment, or some combination of factors.

Despite the increased awareness, Legionnaires’ Disease cases are likely underdiagnosed, due to the similarities in symptoms with typical pneumonia cases. A recent study from the CDC estimates that the true number of Legionnaires’ Disease cases is 1.8 to 2.7 times higher than what is reported.

A Legionnaires’ Disease outbreak at your facility will cost you a lot more than just the mitigation expenses. You’ll face the risk of a complete shut-down of the water system, which will interrupt your daily operations. You’ll possibly face a permanent risk to your reputation (especially if the case is high profile or covered in the news). And finally, you could face litigation – which could cost your facility millions.

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Is Your Facility At Risk For Legionella?

All potable water is at some risk for Legionella under the right circumstances, but if your building meets any of the following criteria, you’re at a higher risk:

  • Your building has been vacant or shut down for more than ten days
  • Your hot water temperature is set outside the recommended guidelines for controlling Legionella
  • You don’t have a treatment program for aerosol-generating devices, pools, spas, humidifiers, or cooling tower systems
  • Your building meets the characteristics detailed in ASHRAE 188, including:
    • Multiple housing units with one or more central potable hot water systems
    • Over 10 stories tall (included levels below grade)
    • The building is a healthcare facility with patient stays exceeding 24 hours
    • Contains one or more areas for the purpose of housing or treating occupants for burns, chemotherapy for cancer, or solid organ transplantation or bone marrow transplantation
    • Contains one or more areas for the purpose of housing or treating occupants that are immunocompromised, at-risk, taking drugs that weaken the immune system, have renal disease, diabetes, or chronic lung disease
    • The building is intended to house occupants over the age of 65

Treatment Methods for Legionella In Potable Water

Treating Legionella can be straightforward and there are multiple options for treatment, depending on your situation.

First, know that there are two categories of remediation:

1. Focal Remediation

This means that the treatment is applied at the source that tested positive for Legionella bacteria. This is recommended for domestic water systems when Legionella is present in less than 30% of the water samples tested, or if the amount of Legionella isolated from a particular device (aerosol-generating device, spa, pool, etc.) exceeds the recommended threshold.

2. Systemic Remediation

This means that you’re treating your entire water system. This is recommended for domestic water systems when Legionella is present in more than 30% of the water samples tested, or if the amount of Legionella isolated from a cooling tower system exceeds the recommended threshold.

Treatment Methods for Potable Water

  • Super-Heating (hot water systems) – can be used as a reactive or proactive measure
  • Chlorine dioxide – typically used as a proactive measure
  • Point-of-Use Filtration – can be used as a reactive or proactive measure

NOTE: You may be exceeding normal limits temporarily (while you mitigate), but the systems will come back to an acceptable level after the remediation is complete.

People often focus on Legionella specifically, but lead, copper, and other materials can also be present in stagnant water. That’s why it’s a good idea to flush your water systems regularly if they are not being used normally – see our list below.

5 Things To Do Right Now To Improve Water Safety At Your Facility

  1. Develop a Water Safety Management Program & form a Water Safety Team.
  2. Flush stagnant or reduced-use potable systems (weekly at a minimum) utilizing both hot and cold water by running the taps on sinks and showers, and flushing your toilets.
  3. Keep your hot water set at the recommended range to kill Legionella, while still keeping it at a safe temperature for bathing or washing hands. At 140°F, Legionella is killed in approximately 30 minutes, but you may want to consult with your mechanical contractor for a recommendation for your system and/or follow local codes for this setting.
  4. Conduct regular testing in accordance with your Water Safety Management Plan.
  5. Partner with a professional water treater to help you monitor and treat your water systems.

If you need help with any of these tasks, HOH can lend a hand.

Water Management Team Worksheet

How We’re Helping With Clean Drinking Water

As I mentioned earlier, we’re fortunate here in the US to have a steady and ample supply of potable water. At HOH, we’re doing our part to safeguard that supply for our customer facilities and their many thousands of occupants.

But in other parts of the world, the need is far more challenging. In developing countries, families have to walk an average of nearly four miles (six kilometers) just to find drinking water, and it may not be clean or safe. A few years ago, we embraced this water crisis as part of our company mission.

This year, we had 320 employees, colleagues, customers, family and friends join Team HOH to support the World Vision 6k for Water, which means we provided 1,200 people with clean water for a lifetime. We’re proud to be part of this effort and welcome all to help us support this great cause.

If you’d like to donate to World Vision to help end the world water crisis, please visit here.