Guidance Document_Routine Legionella Testing for Buildings_April 2021.pdf

Guidance Document

GD-1061-3.0

Routine Environmental Sampling of Building Potable Water Systems for Legionella and Other Parameters in Water in Accordance with VHA Directive 1061

Supplementary document to:

VHA Directive 1061, “Prevention of Healthcare-Associated Legionella Disease and Scald Injury From Water Systems” (published February 2021)

April 2021 https://vaww.visn23.portal.va.gov/min/SiteDirectory/mm/Logos/New%20Signature%20with%20VHA.jpg

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THIS IS AN INTERNAL VETERANS HEALTH ADMINISTRATION DOCUMENT.

This Guidance Document is an internal Veterans Health Administration (VHA) document that was produced by the VHA National Infectious Diseases Service (NIDS) and the VHA Office of Healthcare Engineering (OHE) with input from VHA environmental water work groups, composed of staff from VHA Central Office, Networks and facilities. The document resides at the “Water Safety Management and Legionella Resources” intranet site (http://vaww.hefp.va.gov/healthcare-engineering/water-safety-management-legionella) at the “VA/VHA Policies, Guidance & Supplements” tab.

Questions regarding environmental testing requirements, results, and reporting for Legionella and/or physical/chemical parameters in water may be directed to OHE at VHAhealthcareeng@va.gov and NIDS at VHANIDSWaterSafety@va.gov.

Questions regarding occupational safety and health related to environmental testing for Legionella may be directed to the VHA Office of Occupational Safety Health and GEMS at (412) 999-3727.

Additional resources can be found at the VHA “Water Safety Management & Legionella Resources” intranet site: http://vaww.hefp.va.gov/healthcare-engineering/water-safety-management-legionella

Version History

Document Number Date Description/Changes

GD-1061-3.0 April 2021

Initial release of the Guidance Document to provide supportive information to VHA Directive 1061 (February 16, 2021) with respect to routine environmental testing for Legionella and other parameters in building potable water systems.

http://vaww.hefp.va.gov/healthcare-engineering/water-safety-management-legionella mailto:VHAhealthcareeng@va.gov mailto:VHANIDSWaterSafety@va.gov

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Table of Contents

1. Purpose and Scope

2. Background

2.1 Legionella and Building Water Systems

2.2 VHA Policy for Routine Environmental Testing for Legionella and Associated Parameters

3. Sample Site Selection

3.1 Guidance for Sample Site Selection

3.2 Consideration for Collection of Additional Environmental Samples

4. Order and General Steps for Taking and Processing Samples from an Outlet

4.1 Order of Taking Samples

4.2 Sampling for Legionella

4.3. Sampling for Physical and Chemical Parameters (Temperature, pH, Biocide)

5. Documentation, Reporting and Interpretation of Results

5.1 Documentation of Results

5.2 Reporting of Legionella Testing Results

5.2.1 Water Safety Management Tool

5.2.2 Issue Brief Reporting of Legionella Testing Results

5.3 Interpretation of Legionella Results

5.3.1 Interpreting Legionella results for understanding implementation of engineering controls ... 15

5.3.2 Interpreting Legionella results for remediation decisions

5.4 Interpretation of Biocide Results

5.5 Interpretation of Temperature Results

5.6 Interpretation of pH Results

Appendix A: References

Appendix B: Personnel Considerations for Environmental Sampling of Potable Water Systems for Legionella

B-1 Employee Health Considerations

B-2 Sampler Competency

Appendix C: Quick Reference Guide – Building Routine Environmental Sampling

Appendix D: Routine Sampling for Detection of Legionella in Potable Water

D-1 Sample Criteria for Environmental Testing to Detect Legionella in Potable Water Systems

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D-1.1 Requirements

D-1.2 Guidance on water volume when collecting samples for Legionella detection

D-1.2.1 Amount of Water to Be Collected

D-1.2.2 Documentation of Water Volume

D-1.3 Collecting Water Samples from Outlets for Legionella Testing

D-1.4 Collecting Water Samples from Ice Machines for Legionella Testing

D-1.5 Collecting Water Samples from Hot Water Tanks for Legionella Testing

D-2 Types of Tests Allowed by VHA Policy for Legionella Detection in Routine Samples

D-2.1 Polymerase Chain Reaction (PCR)

D-2.2 Culture Detection

D-3 Laboratory Selection for Detection of Legionella from Environmental Samples

D-3.1 Information about Accreditation

D-3.2 Information about Proficiency Testing

D-3.2.1 Culture Proficiency Testing

D-3.2.2 PCR Proficiency Testing

D-3.3 Other Laboratory Guidance and Information

Appendix E: Measurement of Physical and Chemical Parameters – General Information and

Selection of Equipment

E-1 Water Temperature

E-1.1 General information on Water Temperature Measurement

E-1.2 Selection of Equipment for Measuring Water Temperature

E-2 pH

E-2.1 General Information on pH

E-2.2 Selection of Equipment for Measuring pH

E-3 Biocides

E-3.1 General Information on Biocides

E-3.2 Selection of Equipment for Measuring Biocides

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1. Purpose and Scope

Purpose: The purpose of this document is to provide technical guidance for potable water sampling in support of the requirements in Appendix C of VHA Directive 1061 pertaining to environmental validation of Legionella prevention in building potable water systems. The document focuses on environmental testing procedures related to the routine testing of the water distribution system for Legionella, water temperature, biocide residual and pH (i.e., the parameters recorded for potable water in the Water Safety Management Tool database).

Scope: This document pertains only to routine environmental testing for Legionella in building potable water systems. Guidance for the following testing is outside the scope of this document:

• Routine testing of cooling tower water for Legionella (see Appendix D of Directive 1061 for Legionella testing and Engineering Standard ES-2019-001 for operation and maintenance requirements for cooling towers).

• Additional testing of building potable water systems (e.g., for post remediation, case investigations, or routine/continuous monitoring of engineering controls throughout the system) is outside the scope of the document since details will be dependent on local findings and factors. NOTE: Consultation from the Office of Healthcare Engineering (OHE) and/or the National Infectious Diseases Service (NIDS) is available for assistance.

• Clinical Legionella testing (see the Guidance Document entitled “Diagnosis of Pneumonia Caused by Legionella, and Considerations for Healthcare Association” for information on clinical testing. This document can be found at the resources intranet site:http://vaww.hefp.va.gov/healthcare-engineering/water-safety-management-legionella)

This document is structured in sections that follow the general order of conducting the routine testing for Legionella and other parameters: sample site selection, order and steps for taking water samples at an outlet, processing water samples, and interpretation of results. Details for some sections are included in Appendices.

2. Background

2.1 Legionella and Building Water Systems

Legionella is the genus name of a Gram-negative bacterium which causes respiratory diseases collectively referred to as legionellosis. Legionellosis includes Legionella pneumonia, traditionally known as Legionnaires’ disease (LD), and Pontiac Fever, a self-limiting respiratory illness. Disease is primarily caused by the species Legionella pneumophila, with L. pneumophila serogroup 1 the predominant etiologic agent. Other species of Legionella can be pathogenic, particularly in transplant and other immunocompromised or high-risk patients.

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Legionella are present in natural bodies of water at low levels but are not known to cause disease from these settings. Rather, disease occurs when the bacteria proliferate in building water systems and are subsequently transmitted to people from fixtures and outlets via aerosolization of contaminated water droplets or aspiration via drinking water. Legionella belong to a group of bacteria referred to as “opportunistic premise plumbing pathogens” because they grow in building water systems and can result in disease in susceptible people if Legionella growth is not controlled in water systems. One common characteristic of premise plumbing pathogens is that they grow in the plumbing system in biofilm, a general term for a group of microbial cells attached to a surface and surrounded by polymers they secrete (see Figure 1). The bacteria in the biofilm are often protected from the biocidal activity of disinfectants in water such as chlorine. Bacteria that become dislodged from the biofilm can float freely to other portions of the water distribution system, including to outlets. These free-floating dislodged bacteria are more susceptible to biocides in the water.

2.2 VHA Policy for Routine Environmental Testing for Legionella and Associated Parameters

Per Appendix C in VHA Directive 1061, processes must be in place at buildings subject to the policy to validate that engineering controls (e.g., water temperatures and biocide levels) are effectively inhibiting the hazardous conditions that can lead to Legionella growth. Environmental validation is the process of routinely testing water from outlets on the building’s potable water distribution system(s) for Legionella to provide an assessment as to whether the engineering controls are preventing growth of a pathogen in a building system. Detection of Legionella, especially in repetitive findings, increasing locations, and/or increasing concentrations over time, indicates that control measures

Figure 1. Schematic of Legionella associated with biofilm in premise plumbing [Image credit: CDC; https://www.cdc.gov/legionella/wmp/overview/growth-and-spread.html.]

Accessed 7/24/2019] https://www.cdc.gov/legionella/wmp/overview/growth-and-spread.html

7 | P a g e are not inhibiting growth and that, in addition to remediation, modifications to the engineering controls may be necessary.

* National Academies of Science, Engineering, and Medicine. 2020. Consensus Study Report: Management of

Legionella in Water Systems.

In addition to testing water samples for the presence of Legionella, associated physical water quality parameters (i.e., water temperature, residual biocide level, and pH) are also collected at the same time to help understand the conditions that may be conducive to Legionella growth, if present. This document provides guidance for collecting and processing samples for these parameters.

References relevant to this Guidance Document are listed in Appendix A. See Appendix B for personnel considerations for environmental sampling and Appendix C (Quick Reference Guide) for a chart that summarizes the environmental sampling steps in this document.

3. Sample Site Selection

Per VHA Directive 1061, at least 20 water samples per quarter are to be collected from outlets for each building under the purview of the policy.

• At least two of the 20 samples must be from a pure cold water source such as ice machines, if present.

• At least two of the 20 samples must be from a pure hot water source (with no mixing valve present) if such water outlets are available.

Buildings with 20 or less outlets are allowed to test 50% of the outlets for each quarter instead of 20 outlets each quarter. The types of water samples taken (hot, cold or mixed) should be based on deliberations of the Facility Water Safety Committee, taking validation needs into account.

Why Focus on Testing at Outlets?

• The requirement to routinely sample the water for Legionella validation testing is rooted in prioritization of a proactive approach to LD prevention, and there is growing consensus for this practice.*

• The water sampling is done at outlets since this is the portion of the building water distribution system(s) to which building occupants are exposed and, therefore, which poses the greatest risk. Understanding Legionella positivity at outlets can provide information on how implementation of engineering controls in the system is affecting areas associated with exposure.

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3.1 Guidance for Sample Site Selection

When deciding on sample sites for water collection, consider the following:

• Prioritize higher risk areas, for example patient care and CLC resident areas.

• Sample locations should be representative of the building’s water distribution system. For example, samples could be taken from outlets in the following areas: at the proximal and distal ends of the system, different loops and/or risers, ice machines, drinking fountains.

• Consideration should be given for sampling some outlets in areas with low water flow, infrequent water use or decreased work activity, if present. Low water flow/use is a known factor that can result in Legionella growth.

• It is important that a comprehensive profile of the building be assessed over time based on sample site selection.

o Therefore, during each round of routine environmental testing, vary a portion of the sampling sites (i.e., choose some new sample sites in addition to some that have been sampled previously) for each testing cycle to achieve a more comprehensive overall assessment of the building’s potable water distribution system.

o In addition to varying some outlets, the Facility Water Safety Committee should also determine (based on the building’s design, previous environmental testing results, and any high-risk inpatient areas), which, if any, sample sites should be tested during each round of testing. Keeping a couple of sites constant may be helpful so comparisons can be made to previous testing results at that same site for a more exact understanding of physical and chemical parameters (and Legionella positivity) over time.

3.2 Consideration for Collection of Additional Environmental Samples

Facilities may choose to increase the number of sample sites beyond the 20 samples per building required by VHA policy. Addition of samples may include an increased number of samples from outlets and/or collecting samples from other parts of the water distribution systems (e.g., hot water tanks, distribution loops). Listed below are several situations in which a facility may choose to conduct additional sampling. This addition of samples beyond the required 20 is optional, and the choice could be made on a quarter to quarter basis as needed or implemented routinely for each quarter, semiannually or annually. NOTE: This list is not inclusive of every situation but provides a basis for the Facility Water Safety Committee to determine if additional sampling should be done.

• Epidemiological linkage of an LD case(s) to the building in the past (ever). In this situation, a recognized pathogenic strain that resulted in disease has been previously associated with the building. Since complete eradication of Legionella from building water systems is unlikely, facilities that have had cases of epidemiologically-linked LD in the past may want to test more sites than required, at least for some of the quarterly testing cycles.

9 | P a g e o The “epidemiological linkage” of an LD case to the VA facility could be temporal or molecular. For a presumptive temporal link, the person was at the VA facility for at least 10 continuous days in the 14 day-period prior to LD symptom onset. If the person was at the VA facility for a portion of the 14 days prior to LD symptom onset (but less than 10 consecutive days), then that would not be a definitive epidemiological link of the case to the facility but it may still warrant consideration for routine extra testing. For molecular epidemiological linkage, a clinical Legionella isolate from the patient with LD and an environmental water Legionella isolate from the VA building are determined to be closely related by a molecular typing method; the duration the patient was in the building is not relevant.

• The building includes units that care for severely immunocompromised patients (e.g., bone marrow transplant units, solid organ transplant units, hematology-oncology units).

• The building is large (e.g., an acute care facility with greater than 500 beds, or a building with extensive square footage) or there is more than one potable water distribution system within the building such that the Facility Water Safety Committee determines that more than 20 samples are needed per quarter to provide sufficient information for making decisions regarding validation of engineering controls.

• The facility is in an area of the country associated with higher incidence of LD.

The time of year may also be a factor in deciding whether or not to increase testing. Refer to the following CDC website for more information on national incidence: https://www.cdc.gov/legionella/health-depts/surv-reporting/2016-17-report-tables/index.html.

• The occurrence of construction activities that could affect the water distribution system (e.g., pressure changes that create the potential for dislodging of biofilm, or the work results in a period of low water flow). All construction projects should assess for these types of disruptions and plan accordingly.

• The occurrence of unplanned disruptions to the water supply either from the municipality or internally that could result in the dislodging of biofilm or changes in water usage.

• The facility is unable to achieve the requirements of the primary prevention strategy (i.e., water temperature and biocide levels) in the building.

• Previous water testing results were extensively positive for Legionella, especially L. pneumophila, and/or the concentration of Legionella was higher than usual.

4. Order and General Steps for Taking and Processing Samples from an Outlet

The collection of water samples may be completed by VHA employees and/or contracted personnel. Personnel considerations relevant to collection of samples are outlined in Appendix B. Regardless of who collects the samples at the facility, taking water samples at each outlet should follow the requirements in VHA Directive 1061 as https://www.cdc.gov/legionella/health-depts/surv-reporting/2016-17-report-tables/index.html https://www.cdc.gov/legionella/health-depts/surv-reporting/2016-17-report-tables/index.html

10 | P a g e well as local processes that should consider the guidance in this document. See Appendix C for a Quick Reference Guide for building routine environmental testing.

4.1 Order of Taking Samples

For routine testing in accordance with VHA Directive 1061, sampling at each outlet is for the purpose of determining the presence of Legionella, as well as understanding water temperature, level of residual biocide and pH in water at/to the outlet. The following order should be used for collection of samples to determine those parameters:

• Take the Legionella sample first. Collect the water sample immediately after opening the outlet without flushing water first.

• After taking the sample for Legionella testing, collect the next immediate water sample (i.e. no flushing) to take the biocide residual reading.

• After taking the sample for the biocide reading, run the water for 60 seconds.

Collect a water sample to measure water temperature and pH.

More detail for each of the above steps is provided in the sections below.

4.2 Sampling for Legionella

Detailed information on sample collection and processing for Legionella detection, including laboratory selection and volume of water to be collected, can be found in Appendix D.

In general:

• For routine environmental water testing, collection of samples of water is required to meet VHA policy. Swab samples may be collected in addition to water samples, but swab samples alone do not meet the requirements in the policy.

• The water sample used for Legionella testing must be collected immediately after opening the tap (i.e., do not flush the water first).

• Sample collection bottles for Legionella testing of water should be clean and sterile. Do not use the water sample collected for Legionella testing to take measurements of the other parameters (biocide residual, temperature, pH), which would increase the risk of contamination of the sample.

• Guidance for determining if water samples are hot water, cold water, or mixed hot and cold water is in Appendix D.

General notes on processing samples for Legionella detection:

• Water samples collected for Legionella detection are to be processed by a laboratory accredited and deemed proficient in accordance with VHA policy (see Appendix D of this document for detailed information on laboratory selection).

NOTE: The processing of the samples to determine Legionella presence is not to be done at the outlet at the time of sample collection.

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• VHA policy allows facilities to choose to screen water samples by polymerase chain reaction (PCR) for the absence of Legionella in the sample (i.e., a “negative screen”), followed by culture of only PCR-positive samples to confirm Legionella presence. Or, facilities could opt to not do any PCR screening and just have all the samples processed by culture. See Appendix D for guidance and information on both the PCR negative screen and culture methodologies.

4.3. Sampling for Physical and Chemical Parameters (Temperature, pH, Biocide)

VHA Directive 1061 requires assessments of the engineering controls at the time and locations that Legionella sampling is done. For this process, testing of the following water parameters must be done at the outlets: biocide residual, water temperature, and pH. See Appendix E in this document for more information on taking readings for each of these parameters.

For measurement of physical and chemical parameters at the selected outlets, the following general guidance is provided:

• Do not use the same water sample collected for Legionella detection for taking physical and chemical measurements.

• When collecting the water for physical and chemical measurements, the containers do not need to be sterile and the same containers can be used for sampling different outlets.

• Processing of samples collected at outlets for physical and chemical parameters should be done immediately after collection of the samples at the outlet.

Shipment of the samples to a laboratory is not necessary.

Reason for Taking Physical and Chemical Readings in Conjunction with Legionella Testing

Purpose: To facilitate an understanding of how the engineering controls are performing in the control of Legionella in the system and how well these controls are performing relative to the outlet being tested. These factors can inform whether controls are appropriately designed and installed to influence Legionella growth at the outlet.

• The results from physical and chemical testing during quarterly Legionella validation testing are best interpreted in conjunction with the results from routine (e.g., weekly) monitoring of these parameters in accordance with Appendix A of VHA Directive 1061.

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Sampling protocol:

• After taking the sample for Legionella testing, open the same side of the tap (hot or cold) and use a clean container to collect the next immediate water sample (i.e., do not flush the water). Use this sample to take the biocide residual reading.

o Follow the manufacturer’s instructions for the biocide residual testing equipment to determine the volume of water to be collected.

• After taking the biocide reading, open the same side of the tap (hot or cold) and let the water run for 60 seconds. Use a clean container to collect the water immediately after the water has run for 60 seconds. Use this sample to take the water temperature and pH readings. NOTE: Often the same probe is used to measure both temperature and pH.

o Follow the manufacturer’s instructions for the temperature/pH testing equipment to determine the volume of water to be collected.

5. Documentation, Reporting and Interpretation of Results

5.1 Documentation of Results

The Facility Water Safety Committee should determine the local process for documenting Legionella and other results (temperature, pH, biocide residual). The purpose of this documentation is to record findings to facilitate data analysis and for future retrieval, as needed.

• The Water Safety Management Tool, which is used to report results to VHA Central Office and the VISN (see section 5.2.1 below), can also be used by the facility as the local repository for testing results. The data reported in this Tool can be used for data retrieval and analysis.

• Document discussions or decision-making related to the results (e.g., in Facility Water Safety Committee meeting minutes).

5.2 Reporting of Legionella Testing Results

5.2.1 Water Safety Management Tool

Once sample test results are received, the information is to be entered into the Water Safety Management Tool (WSMT) at http://vaww.hefp.va.gov/resources/water-safety-management-tool-wsmt. Data should be entered into the Tool within 1 week of receipt of the final Legionella testing results from the testing laboratory. NOTE: The VISN is required to certify by locking the results from its facilities by 45 days after the end of the quarter.

http://vaww.hefp.va.gov/resources/water-safety-management-tool-wsmt

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The results for each sample are to be entered to the WSMT for both Legionella-positive and Legionella-negative samples, along with the additional measurements taken (water temperature, pH and biocide residual level).

See the WSMT User Manual for more detail on reporting requirements and guidance on entering data to the system. The User Manual can be found at http://vaww.hefp.va.gov/resources/water-safety-management-tool-wsmt

5.2.2 Issue Brief Reporting of Legionella Testing Results

There is no national requirement to report routine environmental Legionella testing results to VHA Central Office via the Issue Brief reporting system. Reporting such results is a Facility or Network decision. If it is decided to report routine testing results via Issue Brief, the following guidance is provided for consideration of the type of information to include:

• When reporting positive Legionella results, provide the results on a Building level, not just on a campus level. For example, if there were 3 buildings tested (20 samples per building) and 1 building had 5 positive results, it is preferable to report the findings by building (Building A: 5/20 positive; Building B: 0/20 positive;

Building C: 0/20 positive), as opposed to reporting the results as 5/60 positive for the whole campus.

• For buildings with Legionella-positive results, indicate the type of building (e.g., acute care facility, Community Living Center).

• For Legionella-positive samples, report the type of Legionella detected. If L.

pneumophila was detected, report the serogroup, if known.

• In the Actions section of the Issue Brief, provide a description of what actions were or will be taken to address the situation. It would be helpful to know if there was a change in Legionella-positive results from previous quarters suggesting Legionella growth in the system (e.g., an increase in positive outlets). Consider also reporting any clinical findings and actions (e.g., maintaining heightened awareness for cases was communicated to clinical staff; any healthcare-associated LD cases in the recent past).

5.3 Interpretation of Legionella Results

Legionella results are provided by the laboratory as a quantitative assessment (i.e., concentration) of the amount of bacteria detected in a sample.

• Legionella concentration by culture methods is usually reported as colony forming units per milliliter (CFU/ml). Legionella concentration by PCR is usually reported as genome units per milliliter (GU/ml). Both are quantitative measurements, but a precise method to compare CFU/ml and GU/ml for a sample is yet to be established. NOTE: Some laboratories report results per liter instead of per milliliter. If this is the case, then the concentration value should be

14 | P a g e divided by 1000 to represent concentration as CFU/ml. For example, a concentration of 2000 CFU/liter is equivalent to a concentration of 2 CFU/ml.

• Legionella-negative samples from culture methods are usually reported as “not detected”, or something similar, or as an indication that the sample is below a reporting limit (e.g., “<0.1 CFU/ml”). Legionella-negative PCR results (if the PCR negative screen option is chosen) are usually reported as “not detected” or below a reporting limit.

• For Legionella-positive samples by culture, laboratories normally report samples as “positive” or “detected” and/or provide the CFU/ml concentration detected for the sample measurement. Samples may have a fractional amount of bacteria (e.g., 0.5 CFU/ml). This result occurs, for example, in the event that a volume of water is concentrated at the lab to increase detection sensitivity.

o A sample may have a concentration (CFU/ml) below the lab’s limit of detection and still be reported. This indicates that, although low, Legionella was detected in the sample and should be factored into facility decision-making when determining the extent of remediation, if necessary.

The results of the environmental water testing are to be shared with the Facility Water Safety Committee as soon as the results are returned from the lab for analysis and action, if needed. Detection of Legionella in routine water samples precipitates two key actions that will require interpretation of the results:

• assessment of routine engineering controls, and

• determination if remediation is needed.

Considerations for each of these actions is described in more detail below. However, since the reasons for Legionella growth and criteria for remediation are situation-dependent and building-specific, detailed national standardized responses and steps are not possible. Rather, guidance is provided to facilitate local decision-making.

KEY POINT: Over time, each Facility Water Safety Committee should increase knowledge about their water systems to iteratively inform how to interpret and respond to Legionella-positive water samples.

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5.3.1 Interpreting Legionella results for understanding implementation of engineering controls

The following guidance is provided for optimizing the use of environmental Legionella data:

• Review Legionella data on a building level. There may be more than one building on a facility campus for which routine environmental Legionella data are collected. Since several factors within a building can affect the engineering controls intended to limit Legionella growth, it would be prudent to evaluate quarterly Legionella results on a building level, not only on a campus-wide level.

o When determining the percent of Legionella-positive samples during routine testing, determine the percentage for each building. If the percentage is determined only on a campus-level, an incorrect impression about Legionella control could be assumed at some buildings (see Figure 2). Evaluating results on a building level can help prioritize which buildings need the most attention for optimizing implementation and can also alert to when conditions in a building have changed and risk to occupants may be increased.

o It could be helpful to review the Legionella results for each quarter (especially positive results) by overlaying the data on the building water system schematic. This could highlight certain parts of the water system that are routinely positive and in need of corrective actions. Noting areas or water system sections that are habitually Legionella-negative could also assist in understanding the water system. NOTE: Interpretation of Legionella results in this fashion should include assessment of the physical and chemical data also collected for the samples to get a more comprehensive assessment of Legionella-control in the building.

How Routine Legionella Testing Informs Legionella Prevention Plans

The primary purpose for doing routine water testing for Legionella is to validate that engineering controls are effectively controlling Legionella growth in the building water system.

• In a well-managed system, routine Legionella positivity should be undetectable or low, consistently.

• If a building starts out with higher Legionella positivity, routine testing over time should show a downward trend in positivity as engineering controls are better implemented.

• Upward trends in Legionella positivity, or unchanging high positivity, indicate that conditions are conducive to Legionella growth and controls need to be reviewed, optimized, or changed.

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• Analyze Legionella data based on the reason the samples were taken. When grouping data together to understand how well engineering controls are limiting Legionella growth (e.g., by determining the percent of samples that are positive), only include the initial routine quarterly sampling results in the analysis. Do not, for example, also include the results of samples taken after remediation. Since remediation is intended to reduce Legionella positivity, including post-remediation testing results with the routine sampling results could lower the percent positivity for the building and give a skewed impression that Legionella growth is being controlled.

• Analyze Legionella data by the type of water sampled. Analyze the data separately for samples taken from pure cold water sources, pure hot water sources, and mixed hot/cold water sources (i.e., outlets with mixing valves). This can help assess if one type of water is more associated with Legionella positivity than others.

• Trending Legionella data over time. It is recommended that the Facility Water Safety Committee review trends in Legionella testing results over time.

Increases in the percent of Legionella-positive samples and/or the concentration of Legionella in the samples compared to previous quarters can indicate that Legionella are proliferating in the building water system(s). In these situations, assess the implementation of engineering controls and adjust as needed to optimize Legionella control.

o When Legionella-positive results in a building increase substantially in a quarter (i.e., more outlets are positive, and/or the concentration of Legionella detected is much higher), this could suggest that something about the system operation or engineering controls changed (e.g., a change in water pressure, a change in biocide residual level coming into

Figure 2. Viewing Legionella percent positivity by healthcare system versus by individual buildings. In this example, only viewing the data by compiling the results of all four buildings in Healthcare System “A” into one graph (left) masks the results from Building 1, which may need to be prioritized for optimization of engineering controls.

17 | P a g e the building, a change in hot water tank temperature setting). It would be prudent to try to determine if anything changed that could be corrected or adjusted, and/or if additional actions need to be implemented to limit Legionella growth.

5.3.2 Interpreting Legionella results for remediation decisions

VHA Directive 1061 provides the minimum criteria for determining the extent of remediation needed on a building level based on Legionella positivity (See Appendix C of the Directive for criteria and required actions).

Legionella are natural water pathogens; the presence of Legionella in building water systems found in routine testing (and in the absence of an outbreak) is not necessarily indicative that LD cases will occur. However, healthcare facilities are known to have occupants at higher risk for LD, and LD in hospitalized patients can be very severe.

Therefore, in addition to using the routine testing results for the primary purpose of understanding if the engineering control measures are effective, VHA facilities also need to assess the results from the perspective of reducing potential risk to building occupants. In contrast to the previous policy (VHA Directive 1061, 2014), the current VHA Directive 1061 (2021) allows for more flexibility in decision-making at the local level to determine potential risk to building occupants and commensurate actions to reduce the potential risk. In that regard, it is also a local decision if remediation will be implemented more stringently than required in the Directive.

In general, remediation is required when L. pneumophila is detected in at least one sample at a concentration of 1 CFU/ml or higher.

• These criteria do not apply to areas where high risk patients are housed:

transplant units, protective environments, hematology-oncology units, any other areas or buildings deemed “higher risk” by the Facility Water Safety Committee (e.g., past cases of HCA LD definitely associated with the building). In these situations, any type of Legionella and any concentration triggers the remedial actions required by policy.

• The Facility Water Safety Committee can decide that other buildings or areas not deemed to be “higher risk” should perform remediation if any Legionella are detected at any amount. That is, the presence of L. pneumophila at greater than or equal to 1 CFU/ml as a trigger for remediation is a minimum requirement and facilities have the option to choose more stringent triggers for action based on local data, patients, or any other considerations.

o For example, it may be decided that implementation of engineering controls is not optimal in a hospital building and routine positivity of non-pneumophila species will trigger remediation. Or, it may be decided to implement this more stringent trigger at the hospital because of a few past LD cases that were possibly associated with the building.

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• The policy requires use of a “graded response” approach to determining the extent of remediation needed. This allows for an assessment of how extensively the potential risk is in the building.

o The facility no longer is required to take additional samples in the area if only one outlet is positive. This is a local decision as to whether such additional sampling is needed. Reviewing data from past quarters can help inform how extensively the area should be remediated.

Remember that the primary purpose of doing routine Legionella testing is to assess whether the implementation of engineering controls to limit Legionella growth needs to be changed or optimized. If a facility finds that it is consistently remediating the water system after each round of quarterly testing (beyond just remediating one or two outlets), then that is an indication for the Facility Water Safety Committee to assess the Legionella prevention plans, engineering controls, decision-making, and actions.

5.4 Interpretation of Biocide Results

The biocide levels collected during routine environmental validation testing must be reviewed for compliance with local policy and the Directive, and compared to the system monitoring data obtained for that area.

If the sample is from a fixture that is not supplied by a mixing valve and has separate connections to the hot and cold water distribution system, the following conclusions may be drawn. The biocide level at the fixture (hot and cold outlet) should match the level within the system (hot or cold system) that the facility has determined as a minimum. If the biocide level at the fixture is significantly below the biocide level established in the system, the cause must be investigated and engineering controls modified accordingly (including consideration for routine flushing of the water at the outlet).

If the sample is taken from a fixture equipped with a mixing valve, it must be compared to the established minimums in the hot and cold water distribution system. If the values are below those in the hot water or above those in the cold water further investigation should be done as to the cause and engineering controls modified accordingly. This is based on the assumption that the hot water system will burn off the biocide more quickly due to the temperature. If the hot water system has a chlorination system then the data will need to be looked at in more detail to understand the action of mixing valves and impacts on biocide residual levels.

If there is difficulty in interpreting the results and how they relate to Legionella positivity at outlets, consider taking additional water samples for biocide testing. For example, if the biocide residual was determined to be low, flow the water for at least 60 seconds at the same outlets tested previously and take an additional sample to see if the biocide level is more in alignment with the biocide level expected in the system (i.e., an increased amount of biocide from the first sample); if the biocide residual level is not increased from the first sample, then it may be that the system biocide level is low and

19 | P a g e will need to be looked into to determine the cause and adjustments/corrections made to the system or engineering controls. Another example is to take samples at other outlets on the same hydraulic loop without and with flowing the water to assess delivery of biocide to the loop. If the biocide level at the outlets increases to system levels after flowing the water, then that indicates that water is stagnating in the system and biocide level is decreasing over time. In this situation, periodically flushing outlets in low water flow areas may be needed to increase routine biocide levels at the outlets.

Pay particular attention to water sources that have habitually low biocide residual readings, especially compared to other readings for the quarter. This may indicate an issue with delivery of biocide to certain areas or devices. For example, if biocide residual levels are low at drinking fountains but not from other outlets in the area it may indicate low flow, impacts of filters, or that the loop is separate. The cause of the disparity must be investigated and rectified. NOTE: Charcoal filters are often used on drinking fountains and ice machines to improve taste. However, charcoal filters will remove biocide residual and leave the device vulnerable to Legionella growth.

Therefore, to reduce risk to building occupants, charcoal filters should not be used on these devices.

5.5 Interpretation of Temperature Results

The water temperature data collected during environmental validation testing must be reviewed for compliance with the Directive, and compared to the system monitoring data obtained for that area.

If the sample is from a fixture that is not supplied by a mixing valve and has separate connections to the hot and cold system, the following conclusions may be drawn.

• If the sample temperature is within the facility’s potable water distribution system control limits (i.e., 124°F) at least and the Legionella result is negative. it is likely that the control is effective. However, it should be noted that scald risk in this situation is very high and that should be evaluated as well for risk to end users (e.g., patients, visitors and staff). NOTE: Extreme care should be taken when sampling water from outlets without mixing valves to avoid scald injury.

• If the sample temperature is not within the facility’s potable water system control limits and the fixture does not attain a temperature of 124°F or greater for hot water after opening the outlet and running the water for 60 seconds, then the fixture supply line should be reviewed to determine the potential causes including excessive supply pipe run-out distance, size or conditions that may contribute to increased heat transfer between the supply pipe and its surroundings (e.g., lack of insulation or distance to adjacent piping, hot or cold air source). A review of hot water temperature in the main branch supplying the line may be needed to fully interpret results.

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If the sample is taken from a fixture equipped with a mixing valve, water temperature data must be compared to the fixture mixing valve set point of 110°F.

• If the water temperature reaches 110°F (+/- 7°F) after 60 seconds of flowing the water, it can be deduced that the system it is connected to is providing water at or above 110 F; however, it does not ensure the system is within the defined distribution temperature limit.

• If the water at the fixture does not attain a temperature of 110°F after running it for 60 seconds, the fixture supply line should be reviewed to determine the potential causes including excessive supply pipe run-out distance, size or conditions that may contribute to increased heat transfer between the supply pipe and its surroundings. The system should also be sampled to verify that the hot water supply to the branch is 124°F or greater. Modifications to the engineering controls should be implemented. Further, the fixture should be put on a flushing schedule as the data are indicative of an issue with implementation of engineering controls.

If there is difficulty in interpreting the results and how they relate to Legionella positivity at outlets, consider taking additional water samples for water temperature testing. For example, if the water temperature was determined to be low compared to the circulating water temperature in the branch, flow the water until the maximum water temperature is reached. If the maximum temperature is below the expected temperature, further assessment is needed (e.g., distance of outlet from main circulating system and/or the temperature in the circulating system). It should not take longer than 60 seconds for the water temperature in the circulating system to reach outlets. Another example is to take samples at other outlets on the same hydraulic loop without and with flowing the water to assess delivery of temperature to other outlets on the loop.

5.6 Interpretation of pH Results

The pH levels collected during environmental testing must be reviewed and compared to the system monitoring data obtained for that area. Generally, pH will not change from the level measured through continuous monitoring at the supply to the building unless treatment is taking place. If the measurement at the fixture is significantly different than the data obtained in continuous monitoring, further investigation should be done as to the source of the deviation and the engineering controls modified accordingly.

If pH is consistently high or low then the efficacy of the biocide can be impacted.

NOTE: If using chlorine as a biocide and a high pH (i.e., over 8.5) is found then its use is impacted negatively. Therefore, if the environmental Legionella testing is found to be positive, it may be necessary to meet with the municipality to determine if they can lower the pH or if another action is necessary.

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Appendix A: References

APIC Text of Infection Control and Epidemiology. Online version. Chapter 83.

Legionella pneumophila by JE Stout and AM Goetz. 2019.

https://text.apic.org/toc/healthcare-associated-pathogens-and-diseases/legionella-pneumophila

CDC. What owners and managers of buildings and healthcare facilities need to know about the growth and spread of Legionella.

https://www.cdc.gov/legionella/wmp/overview/growth-and-spread.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Flegionella%2Fwater-system-maintenance%2Fgrowth-and-spread.html Page last reviewed April 30, 2018.

Accessed April 5, 2021.

CDC. Legionellosis Case Report Form (January 2020) http://www.cdc.gov/legionella/downloads/case-report-form.pdf.

CDC. Environmental Investigation Resources. https://www.cdc.gov/legionella/health-depts/environmental-inv-resources.html Last reviewed April 30, 2018. Accessed April 5, 2021.

[NOTE: This link provides assessment and sampling tools to assist in the environmental component of LD outbreak investigations. However, some of the information may be helpful for routine sampling as well.]

CDC. Toolkit for Controlling Legionella in Common Sources of Exposure.

https://www.cdc.gov/legionella/wmp/control-toolkit/index.html. Last reviewed February 3, 2021. Accessed April 5, 2021.

National Academies of Science, Engineering, and Medicine. 2020. Consensus Study Report: Management of Legionella in Water Systems. Washington, DC. The National Academies Press. https://doi.org/10.17226/25474.

VHA Directive 1061. Prevention of Healthcare-associated Legionella Disease and Scald Injury from Water Systems.

https://vaww.va.gov/vhapublications/ViewPublication.asp?pub_ID=9181. Published February 16, 2021.

VHA Directive 7702. Industrial Hygiene Exposure Assessment Program.

https://www.va.gov/vhapublications/ViewPublication.asp?pub_ID=3198. Published April 29, 2016. NOTE: VHA Directive 7702 was undergoing review at the time this Guidance Document was issued; any updated version of the Directive can be found at the VHA website for publications: https://www.va.gov/vhapublications/publications.cfm?pub=1 https://text.apic.org/toc/healthcare-associated-pathogens-and-diseases/legionella-pneumophila https://text.apic.org/toc/healthcare-associated-pathogens-and-diseases/legionella-pneumophila https://www.cdc.gov/legionella/wmp/overview/growth-and-spread.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Flegionella%2Fwater-system-maintenance%2Fgrowth-and-spread.html https://www.cdc.gov/legionella/wmp/overview/growth-and-spread.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Flegionella%2Fwater-system-maintenance%2Fgrowth-and-spread.html https://www.cdc.gov/legionella/wmp/overview/growth-and-spread.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Flegionella%2Fwater-system-maintenance%2Fgrowth-and-spread.html http://www.cdc.gov/legionella/downloads/case-report-form.pdf https://www.cdc.gov/legionella/health-depts/environmental-inv-resources.html https://www.cdc.gov/legionella/health-depts/environmental-inv-resources.html https://www.cdc.gov/legionella/wmp/control-toolkit/index.html https://doi.org/10.17226/25474 https://vaww.va.gov/vhapublications/ViewPublication.asp?pub_ID=9181 https://www.va.gov/vhapublications/ViewPublication.asp?pub_ID=3198 https://www.va.gov/vhapublications/publications.cfm?pub=1

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Appendix B: Personnel Considerations for Environmental Sampling of

Potable Water Systems for Legionella

B-1 Employee Health Considerations

NOTE: Based on the scope of the guidance document, this section pertains to employee safety during the collection of routine water samples for Legionella detection.