Legionnaires’ disease is a serious form of pneumonia caused by Legionella bacteria that grows in a building water system and becomes aerosolized. When the bacteria is aerosolized and inhaled, it gets into the lungs where it can grow and cause an infection and pneumonia or fluid in the lungs known as Legionellosis or Legionnaires’ disease. People with a suppressed immune system have an increased susceptibility.  

When Legionella grows to high numbers it can be spread to susceptible hosts when it is aerosolized. In many applications aerosolization of water cannot be avoided, such as in showers, cooling towers and fountains. Instead of trying to prevent aerosolization, the focus should be on preventing bacteria growth in the building water system using physical or chemical control methods.  

Even with chemical or physical controls, Legionella can grow in dead legs or seldom used parts of building water systems that are warm, wet, and where there are nutrients that are a food source for the bacteria. The key is to eliminate growth conditions and minimize or eliminate dead legs and seldom used branches. This can be accomplished with proper system design, installation and maintenance.

Centers for Medicare and Medicaid Services
(CMS) Requirements

On June 9, 2017, the “Director of the Centers for Medicare and Medicaid Services’ Committee on Quality, Safety and Oversight,” issued a memorandum to State Hospital Survey Agency Directors requiring that all inspectors that inspect facilities that receive Federal reimbursement money for Medicare & Medicaid patients comply with a new directive. The Agency director, David R. Wright, has since issued a revision to that memo on July 6, 2018 to State survey agency directors to further clarify the requirements for facilities to have water management programs that comply with ASHRAE Standard 188.  

I serve on the ASHRAE Standard 188 committee. The memo addresses the CDC statistics about the drastic rise in reported cases of Legionnaires disease since 2000. I applaud CMS for issuing their memo because it was the first nationwide document requiring hospitals and nursing homes to have water management plans to reduce Legionella risk in healthcare facility water systems to prevent cases and outbreaks of Legionnaires’ Disease. The City of New York and the State of New York now have requirements for buildings to register cooling towers which were determined to be the cause of a large outbreak in New York City in the Summer of 2015 and this has prompted a need to provide water management plans for building water systems in New York. Other cities, counties and local jurisdictions are considering adopting similar language, and there is a need for uniform legislative language that can be easily adopted so that enforcement is consistent across the country. 

The Centers for Medicare & Medicaid (CMS) directive requires’ Medicare and Medicare/Medicaid certified healthcare facilities to have water management policies and procedures to reduce the risk of growth and spread of Legionella and other opportunistic pathogens in building water systems.  

Facilities must have water management plans and documentation that, at a minimum, ensure each facility:  Conducts a facility risk assessment to identify where Legionella and other opportunistic waterborne pathogens could grow and spread in the facilities building water systems; Develops and implements a water management program that considers the ASHRAE industry standard and the CDC toolkit; Specifies testing protocols for verification and validation of acceptable ranges for control measures and how to document the results of testing and the corrective actions that must be taken when control limits are not maintained; and Maintains compliance with other applicable Federal, State and local requirements. 

Long Term Care (LTC) facility surveyors will expect that a water management plan or program (which includes a facility risk assessment report and development of a system flow diagram by qualified individuals and testing protocols) is available for review but will not cite the facility based on the specific risk assessment or testing protocols in use. 

The Centers for Medicare and Medicaid “Guidance” and “Process” for LTC surveyors will be communicated in an upcoming survey process computer software update to CMS LTC inspectors.

The Centers for Medicare & Medicaid (CMS) policy memorandum is available online at: https://www.cms.gov/Medicare/Provider-Enrollment-and-Certification/SurveyCertificationGenInfo/Downloads/QSO17-30-HospitalCAH-NH-REVISED-.pdf

Water Conservation Efforts 

According to the CDC, during the period between 2000 and 2014, the rate of reported cases of legionellosis increased 286 percent in the U.S., with approximately 5,000 cases reported to the Centers for Disease Control and Prevention (CDC) in 2014. It is my opinion that more likely than not that this upward trend in reported cases is associated with Legionnaires’ Disease and Pontiac fever (a milder, influenza-like illness in the Legionellosis family) is associated with water and energy conservation efforts over approximately the same time period. Many cases still go undetected or unreported and they are often misdiagnosed as simply pneumonia without testing for Legionnaires’ disease. According to the CDC, approximately 9 percent of reported legionellosis cases are fatal. 

In 1992 the Energy Policy Act (EPACT) was the first major water conservation legislation that had mandatory water use reductions for plumbing fixtures. Volunteer programs became popular after they published their energy and water conservation guidelines and many other water conservation programs followed and have become popular via local mandatory requirements or voluntary compliance for a points or award system that rewards building owners with a plaque for the level of compliance. These programs encourage further reductions of water use beyond the limits established in the EPACT and this started to occur around the time period in which the CDC started to document a significant increase in reported cases of Legionnaires disease. There are two EPA studies with the help of four universities under way that are researching the cause and effect relationship between water conservation programs and bacterial growth. Results of these studies should be published in the coming years.

Reductions in water use are contributing to slower water flows in public water mains, which will more likely than not, remain oversized to allow for fire flows. A recent calculation of water flows prior to 1992 and using todays ultra-low flow fixture flow rates shows over an 80 percent reduction in water use. That is good news for water conservation but bad news with respect to water age and chlorine residuals at fixtures. These water-use reduction efforts contribute to aging water and less water treatment chemical residual (Chlorine) at the ends of water mains. Today, it takes about five times longer for water from the treatment plant to reach the farthest customers in the same distribution system.  In the past, (prior to 1992) it took 3 to 4 days for water from the treatment plant to reach the end of a large distribution system under normal flow velocities or usages. With today’s flow rates, it would take about 15 to 20 days for water to reach the end of the same large distribution system.  

Chlorine should last 3 to 4 days and have a measurable residual at the end of the system in 1992, however, chlorine dissipates over time as it reacts with contaminants, pipe materials, temperature, etc., and would not be expected to have a measurable residual that would control Legionella bacteria growth after 15 to 20 days in a water main. In the future, civil engineers may need to explore circulated grids or return water mains with duplex or self-cleaning in-line filter or flushing stations and/or treatment facilities or secondary water treatment stations in the distribution network in order to control bacterial growth throughout longer/larger water utility distribution systems.   

ASHRAE 188 Standard

In June of 2015, an industry standard was published by American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). The standard was titled, “ASHRAE 188-2015: Legionellosis: Risk Management for Building Water Systems.” Within days of publication of the Standard, a Legionnaires disease outbreak was identified in New York City in the Summer of 2015, it was reported that about 130 people in New York City were infected with Legionnaires', the majority of them were in the Bronx, causing over a dozen people to die and others in New York became ill with Legionnaires disease, but were not in the Bronx. In that investigation, a cooling tower was implemented in the Bronx, but the others who lived in another area of the city more likely than not did not get if from that cooling tower.  

There are other contributing factors to widespread distribution of Legionella bacteria.   Legionella can get introduced into building water systems by a number of causes including but not limited to Water main breaks, fire events, changes in water chemistry, system shut-downs, air in the piping system, etc. Before the water with bacteria is aerosolized, it must first be introduced into the building water system and experience conditions where it can grow to numbers that are high, which would increase the efficiency of the transmission to humans when it is breathed in. This can happen in building water systems that are poorly designed or poorly maintained.

Aerosolization, Maintenance and
Water Management Plans

There are several common sources of fixtures and equipment or building water systems that can aerosolize contaminated water and cause Legionnaires Disease. However, if the water is treated or maintained where it will not support bacteria growth, it will minimize or eliminate the chance of transmitting aerosolized bacteria to susceptible persons. Any system, if not maintained properly, can allow contaminated water to be breathed in by susceptible persons. 

The common thing among most Legionella outbreaks is presence of Legionella bacteria in the utility water source, temperature and environmental conditions ideal for growth, aging water (dissipation of water treatment chemicals). In some cases, poor system design, installation and/or maintenance can significantly increase the chances of Legionella bacteria growing with a number of things that could fill up the pages of this magazine. In many cases, when there are cases of Legionella it can be attributed to there is poor maintenance or lack of maintenance of the building water systems. Each source of aerosolized water requires either regular flushing, control of temperatures, or the addition of secondary water treatment chemicals as part of routine maintenance in order to control the risk of Legionella bacteria growth in each system. This is where a water management plan is important for all buildings.  

A water management plan is the guiding document for a building water system maintenance schedule to help maintenance personnel perform routine maintenance on a schedule that maintains the building water systems in a clean and safe condition. Currently, the facilities mandated for water management plans are healthcare facilities under the CMS program and a few local jurisdictions, like New York, which have mandated registration of Cooling Towers. Local, State and national Government officials should consider mandating a water management program for all commercial buildings that serve the public.  

The water management plans should at a minimum comply with ASHRAE 188, even if the model codes adopt 188 as a mandatory require local jurisdictions should require registration of building water systems which would include a validation test to assure the systems are being maintained. The healthcare industry used to be where the majority of outbreaks occurred, because they are large buildings with susceptible populations. Hotels, waterparks and other public buildings with decorative fountains are increasingly having outbreaks because they have no mandatory requirements to have water management plans. Local jurisdictions should consider registration of more than just cooling towers.     

The ASHRAE 188 standard gives direction on what types of buildings should have water management plans or programs and it gives direction on how to set up a water management team in large or complex buildings where building water systems should be maintained and controlled to reduce the risk of Legionella bacteria growth. The complimentary ASHRAE Guideline 12 document gives further direction on how to control Legionella Bacteria in Building Water systems. ASHRAE is also working on a new standard titled, “ASHRAE 514,” which will be a new standard for Prevention of Injury and Disease Associated with Building Water Systems. 

The CDC toolkit 

In 2016, the CDC and its partners developed a toolkit to facilitate implementation of the ASHRAE Standard. The CDC toolkit was a start, and it calls for water management team members with seven (7) different skill sets as part of the water management team. I have often found a lack of plumbing and mechanical expertise when looking at remediation efforts related to Legionella cases. I also see in many cases, where a water management team, risk assessment team, or remediation team does not have team members with plumbing, or mechanical system knowledge or skills. 

It is important for persons assessing the risk of building water systems to have the skills, ability and knowledge of those systems. They should have the ability to properly draw an accurate system flow diagram showing all of the components and identify the potential risks in the building water systems. The example drawings in the CDC toolkit show process flow diagrams with blocks identifying subject areas and they are poor examples of how system flow diagrams should be drawn.  

I have seen inexperienced risk assessors that are required to develop a flow diagram of a building water system, copy the block diagrams from the CDC toolkit and paste then in their water management plan to serve as their system flow diagram. These copies in no way represent what is happening in a buildings water piping system. Shortcomings in the CDC toolkit demonstrate a need for plumbing and mechanical design professionals to be consulted for updating the toolkit. 

The CDC toolkit is available at: www.cdc.gov/legionella/maintenance/wmp-toolkit.html. 

Epidemiology 

Epidemiology is the study and analysis of the distribution, patterns and determinants of health and disease conditions in defined populations or areas. Epidemiology can also be applied to an analysis of plumbing systems to determine which piping or equipment conditions promote Legionella bacteria growth. 

Epidemiology is the cornerstone of public health, and the outcomes determined from the epidemiology studies or documentation and analysis of the facts can help shape policy, code and standard decisions and by using evidence-based practices for identifying risk factors in building water systems for disease and targets for prevention. Epidemiology through investigations and lab experiments has taught us about what legionella needs to survive and to grow with respect to temperature, pH and nutrients.  

Dead Legs

Dead legs can grow bacteria because of ideal temperatures due to heat conduction into the walls of the branch pipes. High points in piping systems trap air and stagnant water gives off tiny bubbles of gas that can add to air pockets at high points in a seldom used pipe branch (dead leg). These air or gas pockets are compressed as the city water pressure acts on the air pockets and they expand as the water pressures drops during flow.  When the air pockets expand, they cause water in a dead leg to surge back into the main dosing the main with Legionella bacteria from the dead leg. This pressure drop and subsequent dosing of the main with bacteria can happen many times a day during peak flow periods in the main.  This is why dead legs should be kept to no more than about five pipe diameters.  

Tests using clear piping with colored dyes showed water can swirl into a branch with eddy currents at a tee, up to about five times the pipe diameter. Any further than five pipe diameters and the water treatment chemicals may not flow into the branch well enough to control Legionella bacteria growth. 

There are three manufacturers promoting piping systems that flow through branches or flush piping at the ends of seldom used branches. These designs are very popular in Europe where they do not allow water treatment chemicals in some countries and severely limit the levels in other countries causing a demand for flushing and elimination a dead legs or seldom used branches. The manufacturers are: Kemper, Viega and Georg Fischer. These systems have not been overly popular with healthcare design teams in the U.S. yet, because of the concerns over the additional cost for these systems. As awareness of the benefits of these systems increases and as owners realize preventing one case of legionella can save millions in litigation costs for a facility, these systems will soon increase in demand.  

Eliminating dead legs will create the need to reroute piping for equipment bypasses and add shut-off valves with drain valves or flushing valves between the isolation valves for flushing seldom used branches before putting them back into service.

Environmental, clinical, and epidemiologic considerations for healthcare facilities are described in the CDC toolkit and it includes control measures such as physical controls like temperature management, chemical controls such as disinfectant levels, visual inspections for identifying risks, and how to conduct environmental testing for pathogens if environmental testing is done. 

Testing for Legionella simply confirms you have a problem. Testing won’t fix the problem, but it will confirm it is fixed when the corrective actions are taken. Corrective actions should not be a guessing game. They should be done by professionals that know what they are doing.

Tanks Do Not Cause Legionella Bacteria Growth

The CDC toolkit says many outbreaks are linked to environmental reservoirs, such as cooling tower basins or hot water storage tanks in large or complex water systems, including those found in healthcare facilities such as hospitals and long-term care facilities. While this statement is true with respect to what the CDC finds, storage tanks do not cause Legionnaires’ disease any more than an aluminum can causes alcoholism or pencils cause misspelled words.   

This is a major error in the CDC toolkit in that it implies tanks cause Legionella growth.  Because of this language, many facility engineers have asked for the removal of hot water storage tanks from facilities or facility designs. This creates a whole new set of problems. The removal of storage tanks from facilities that experience significant peak hot water loads often leads to periods where the instantaneous water heater systems that replace the tanks cannot keep up with peak demands for hot water, so the natural tendency of maintenance personnel that are faced with numerous calls of not enough hot water during the peak hours, is to increase system temperatures, which has led to many scald injuries and deaths.  

After scald injuries occur, maintenance personnel are usually nervous about scalding issues, so they turn the thermostat down on the instantaneous system to a temperature that promotes Legionella bacteria growth in systems that do not have tanks. Legionella bacteria does not need a tank or reservoir in order to grow. Legionella bacteria will grow anywhere that the conditions are ideal for growth.

Hot water in storage tanks can be easily maintained at temperatures that will pasteurize the hot water in the storage tanks by maintaining temperatures above 140 F, which will kill Legionella bacteria within 32 minutes, or 150 F, which will kill Legionella bacteria in 2 minutes. Hot water storage tanks in large buildings should circulate the hot water through the storage tank and all parts of the building above 124 F. At temperatures above 122 F Legionella bacteria will not grow and multiply. A master, temperature actuated mixing valve conforming to ASSE 1017 should be installed on all domestic hot water systems in order to accurately control the hot water return temperature. Utilizing mixing valves will assure the return temperature is delivered at a constant hot water distribution temperature so that the hot water return pipe after the circulating pump, and before connecting to the water heater, is at or slightly above 124 F.  

Water heater burner thermostats on many water heater models allow temperature fluctuations as much as 15 degrees above and below the thermostat set point, which allows a 30-degree swing in temperature which is not accurate and could promote Legionella bacteria growth in portions of the distribution piping. Therefore, the thermostat dial on a water heater should not be relied upon for accurate temperature control unless the water heater has been certified to the ASSE 1082 water heater temperature control standard. You should also make sure that all plumbing fixtures and points of hot water use have thermostatic or temperature limiting controls adjusted as part of commissioning and routine seasonal maintenance to prevent scalding.

Cooling Tower Basins

Cooling tower basins can be maintained properly by adding water treatment chemicals and flushing or blowing down the cooling tower basins using a conductivity meter to flush water through the basin to lower the conductivity of the water thereby flushing minerals down the drain and lowering the pH levels using a conductivity meter. Water treatment chemical are added based on the make-up water volume to provide proportional chemical control of bacteria in the cooling tower basin. This automated procedure combined with regular monitoring, inspections and scheduled maintenance also minimizes sediment build-up and food sources for bacteria. Constantly monitoring and maintaining condenser water, (cooling tower water) chemicals at levels that will control bacteria growth in the condenser water in the cooling tower basin is how to control bacteria growth.  

It is very simple to control Legionella bacteria in a system, however, in many cases, I see there are repeated outbreaks because there are people that are responsible for maintenance and risk assessments that do not know what they are looking at and are often guessing at solutions. I have always said there needs to be a certification exam for Legionella Risk Assessors. ASSE has started developing a professional qualifications standard, however there is a big push to focus training requirements on Legionella testing requirements which will not control Legionella growth in building water systems. I’m not saying testing is not important, but the most important thing to teach and test for in a professional qualifications standard is knowledge of how the systems and the components work.  

They have not yet decided to add knowledge of plumbing and mechanical systems to the professional qualifications standard, so I hope the ASSE committee developing the standard includes more requirements to trains these people on plumbing and mechanical systems or we will see a lot more five-minute inspections that completely miss the problems in the system while making a sales commission.   

Some states and cities are looking at adopting ordinances to require some form of accountability for controlling bacteria growth in building water systems in the wake of several large outbreaks in recent years where many people were sickened and died.  Keep maintaining your systems in accordance with a water management plan and perform Legionella testing at intervals scheduled by the water management plan and you will be Legionella free.