Influence of Hot Water Temperature and Use Patterns on Microbial Water Quality in Building Plumbing Systems

Tolofari, Dienye; Bartrand, Timothy A.; Masters, Sheldon; Batista, Marylia Duarte; Haas, Charles N.; Olson, Mira S.; Gurian, Patrick L.

doi:10.1089/ees.2021.0272

Cited by 15 publications

(22 citation statements)

References 60 publications

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“…As a result, there is potential for Legionella spp. growth in building plumbing systems in the US, particularly in free chlorine systems, where little residual persists in hot water systems [59]. This is confirmed by the high frequency of Legionella spp.…”

Section: Discussionmentioning

confidence: 84%

Practitioners’ Perspective on the Prevalent Water Quality Management Practices for Legionella Control in Large Buildings in the United States

Singh

Chauhan

Fogarty

et al. 2022

Water

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Managing building water systems is complicated by the need to maintain hot water temperatures high enough to control the growth of Legionella spp. while minimizing the risk of scalding. This study assessed water quality management practices in large buildings in the United States. Surveys conducted with building water quality managers found that more than 85% of buildings have hot water temperatures that are consistent with scald risk mitigation guidelines (i.e., <122 °F/50 °C). However, nearly two thirds and three quarters of buildings do not comply with the common temperature guidance for opportunistic pathogen control, i.e., water heater setpoint > 140 °F (60 °C) and recirculation loop > 122 °F (50 °C), respectively; median values for both setpoint and recirculation loop temperatures are 10 °F (6 °C) or more below temperatures recommended for opportunistic pathogen control. These observations suggest that many buildings are prone to Legionella spp. risk. The study also found that 27% of buildings do not comply with guidelines for time to equilibrium hot water temperature, over 33% fail to monitor temperature in the recirculation loop, more than 70% fail to replace or disinfect showerheads, more than 40% lack a written management plan, and only a minority conduct any monitoring of residual disinfectant levels or microbiological quality. Given the rise in Legionellosis infections in recent years, coupled with highlighted water quality concerns because of prolonged water stagnation in plumbing, such as in buildings closed due to COVID-19, current management practices, which appear to be focused on scald risk, may need to be broadened to include greater attention to control of opportunistic pathogens. To accomplish this, there is a need for formal training and resources for facility managers.

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Section: Discussionmentioning

confidence: 84%

Practitioners’ Perspective on the Prevalent Water Quality Management Practices for Legionella Control in Large Buildings in the United States

Singh

Chauhan

Fogarty

et al. 2022

Water

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“…[6][7][8][9][10] Reduced water use is associated with decreased disinfectant residual levels, equilibration of hot and cold water temperatures with building temperature, and potential for increased concentrations of contaminants such as disinfection byproducts, metals, and opportunistic pathogens. [11][12][13][14][15][16][17][18][19][20][21] Legionella pneumophila, the causative agent of Legionnaires' disease and Pontiac fever, was of particular concern because its occurrence is widely assumed to be associated with low water use, [22][23][24][25][26] and disease incidence is rising around the world. [27][28][29][30] However, few studies have investigated its occurrence during extended periods of reduced water use.…”

Section: Introductionmentioning

confidence: 99%

Legionella pneumophilaoccurrence in reduced-occupancy buildings in 11 cities during the COVID-19 pandemic

Dowdell

Greenwald

Joshi

et al. 2022

Preprint

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In spring 2020, reduced water demand was an unintended consequence of COVID-19 pandemic-related building closures. Concerns arose that contaminants associated with water stagnation, such as Legionella pneumophila, could become prevalent. To investigate this potential public health risk, samples from 26 reduced-occupancy buildings across 11 cities in the United States, Canada, and Switzerland were analyzed for L. pneumophila using liquid culture (Legiolert, n=258) and DNA-based methods (qPCR/ddPCR, n=138). L. pneumophila culture-positivity was largely associated with just five buildings, each of which had specific design or operational deficiencies commonly associated with L. pneumophila occurrence. Samples from free chlorine buildings had higher culture-positivity (37%) than chloramine buildings (1%), and 78% of culture-positive samples occurred when the residual was ≤0.1 mg/L Cl2. Although overall sample positivities using culture- and DNA-based methods were equivalent (34% vs. 35%), there was disagreement between the methods in 13% of paired samples. Few buildings reported any water management activities, and L. pneumophila concentrations in flushed samples were occasionally greater than in first-draw samples. This study provides insight into how building plumbing characteristics and management practices contribute to L. pneumophila occurrence during low water use periods and can inform targeted prevention and mitigation efforts.

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“…Pathogens of Interest. NTM were the only opportunistic pathogens consistently found in the sampling data, 23 and for this reason as well as its potential health issues, NTM are the pathogens of interest in this study. NTM are a large diverse group of species in the Mycobacterium genus, and Mycobacterium abscessus complex, Mycobacterium kansasii, Mycobacterium intracellular, and Mycobacterium avium complex (MAC) are among the most frequent species that are recognized as important human pathogens.…”

Section: Overview Of Risk Analysismentioning

confidence: 88%

“…28 The concentration data of NTM were taken from previous studies conducted in cold water plumbing pipes 6 and hot water heater storage tanks. 23 As a conservative assumption, NTM is assumed to be 100% MAC in this study. The studies were conducted in Philadelphia, where monochloramine is used as a secondary disinfectant.…”

Section: Overview Of Risk Analysismentioning

confidence: 99%

“…This mixture would have a temperature of roughly 40 °C and represents a scenario where some degree of influence from the building plumbing system is present in both hot and cold water. The third scenario is termed the water heater scenario, which is based solely on the hot water tank experimental data 23 based on the weighted average of the different experimental conditions studied consisting of 85% of the values at 48 °C and 15% of the values at 60 °C for a final temperature of 49.8 °C. This scenario avoids the possible disproportionate impact of the first flush from the cold water system which comprises 33% of the data in the "blend" scenario.…”

Section: Overview Of Risk Analysismentioning

confidence: 99%

See 1 more Smart Citation

Disability-Adjusted Life Year Frameworks for Comparing Health Impacts Associated with Mycobacterium avium, Trihalomethanes, and Haloacetic Acids in a Building Plumbing System

Tolofari

Bartrand²,

Haas

et al. 2022

ACS EST Water

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To address trade-offs, prioritize, and manage the risks between microbial and chemical risks, the disability-adjusted life year (DALY) approach was utilized. The sampling data from cold and hot water building plumbing in Philadelphia, PA, revealed three classes of health stressors, nontuberculous mycobacteria, total trihalomethanes (THMs), and total haloacetic acids (HAAs). The concentration data specific to the water system were then used to estimate the annual risk due to the Mycobacterium avium complex (MAC), THMs, and HAAs. The results from this study suggest that efforts to reduce the potential health risks from disinfection byproducts should still be given due consideration as the annual DALY of bladder cancer (7.61*10–7) was estimated to be greater than the annual DALY of MAC pulmonary disease (4.74*10–12) by 5 orders of magnitude. The DALYs of both THMs (2.62*10–6) and HAAs (2.60*10–6) in buildings via the ingestion exposure route were higher than the reported threshold of 1 μDALY. Relative to the feed water, water quality changes in the building plumbing substantially increased the DALY impacts for microbial risks but modestly decreased the DALY impacts for chemical risks. While the results are specific to the system considered (e.g., chloramine disinfectant, no detectable Legionella), the study presents a framework for prioritizing among building plumbing microbial and chemical risks.

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Influence of Hot Water Temperature and Use Patterns on Microbial Water Quality in Building Plumbing Systems

Cited by 15 publications

References 60 publications

Practitioners’ Perspective on the Prevalent Water Quality Management Practices for Legionella Control in Large Buildings in the United States

Practitioners’ Perspective on the Prevalent Water Quality Management Practices for Legionella Control in Large Buildings in the United States

Legionella pneumophilaoccurrence in reduced-occupancy buildings in 11 cities during the COVID-19 pandemic

Disability-Adjusted Life Year Frameworks for Comparing Health Impacts Associated with Mycobacterium avium, Trihalomethanes, and Haloacetic Acids in a Building Plumbing System

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