Residential water heater cleaning and occurrence of Legionella in Flint, MI

Rhoads, William J.; Bradley, Taylor N.; Mantha, Anurag; Marr, Linsey C.; Keane, Tim; Pruden, Amy; Edwards, Marc

doi:10.1016/j.watres.2019.115439

Cited by 17 publications

(22 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Routine maintenance and initial startup procedures (e.g., softener resin replacement or cleaning and disinfection, filter replacement) can serve as a starting point. Adapting existing recommendations should focus on ways to fully overturn the storage volume and remove accumulated sediment/biofilm (Masters et al, 2018; Rhoads et al, 2020).…”

Section: Resultsmentioning

confidence: 99%

Considerations for large building water quality after extended stagnation

Proctor

Rhoads

Keane³

et al. 2020

AWWA Water Science

Self Cite

View full text Add to dashboard Cite

The unprecedented number of building closures related to the coronavirus disease (COVID‐19) pandemic is concerning because water stagnation will occur in many buildings that do not have water management plans in place. Stagnant water can have chemical and microbiological contaminants that pose potential health risks to occupants. Health officials, building owners, utilities, and other entities are rapidly developing guidance to address this issue, but the scope, applicability, and details included in the guidance vary widely. To provide a primer of large building water system preventative and remedial strategies, peer‐reviewed, government, industry, and nonprofit literature relevant to water stagnation and decontamination practices for plumbing was synthesized. Preventative practices to help avoid the need for recommissioning (e.g., routine flushing) and specific actions, challenges, and limitations associated with recommissioning were identified and characterized. Considerations for worker and occupant safety were also indicated. The intended audience of this work includes organizations developing guidance.

show abstract

Section: Resultsmentioning

confidence: 99%

Considerations for large building water quality after extended stagnation

Proctor

Rhoads

Keane³

et al. 2020

AWWA Water Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…30,93 However, observed water temperature at distal fixtures may not always be helpful in predicting L. pneumophila concentrations because distal sampling locations acclimate to ambient temperature. 64,86,94 Therefore, approaches that incorporate wholebuilding temperature profiling may be more effective for assessing the influence of hot water temperature on L. pneumophila. 91 Intermittent heating, and other energy-saving methods have previously been linked to lower water qualities due to decreased hot water temperatures in building plumbing.…”

Section: Sample Temperature and Ph Were Not Associated With L Pneumop...mentioning

confidence: 99%

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

Dowdell

Greenwald

Joshi

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…Recirculating systems can also accumulate 3-20 times more sediments [222] arising from corrosion of metallic pipe material and the anode rods [157,[232][233][234]258]. These sediments, which also collect at the bottom of hot water tanks, may serve as an important growth niche within warm regions of hot water tanks where influent cold water depresses temperatures, and there are also relatively low levels of disinfectant and high levels of nutrients for Legionella, heterotrophs, and host organisms [17,259].…”

Section: Hot Water Recirculation Linesmentioning

confidence: 99%

Critical Review: Propensity of Premise Plumbing Pipe Materials to Enhance or Diminish Growth of Legionella and Other Opportunistic Pathogens

et al. 2020

Self Cite

View full text Add to dashboard Cite

Growth of Legionella pneumophila and other opportunistic pathogens (OPs) in drinking water premise plumbing poses an increasing public health concern. Premise plumbing is constructed of a variety of materials, creating complex environments that vary chemically, microbiologically, spatially, and temporally in a manner likely to influence survival and growth of OPs. Here we systematically review the literature to critically examine the varied effects of common metallic (copper, iron) and plastic (PVC, cross-linked polyethylene (PEX)) pipe materials on factors influencing OP growth in drinking water, including nutrient availability, disinfectant levels, and the composition of the broader microbiome. Plastic pipes can leach organic carbon, but demonstrate a lower disinfectant demand and fewer water chemistry interactions. Iron pipes may provide OPs with nutrients directly or indirectly, exhibiting a high disinfectant demand and potential to form scales with high surface areas suitable for biofilm colonization. While copper pipes are known for their antimicrobial properties, evidence of their efficacy for OP control is inconsistent. Under some circumstances, copper’s interactions with premise plumbing water chemistry and resident microbes can encourage growth of OPs. Plumbing design, configuration, and operation can be manipulated to control such interactions and health outcomes. Influences of pipe materials on OP physiology should also be considered, including the possibility of influencing virulence and antibiotic resistance. In conclusion, all known pipe materials have a potential to either stimulate or inhibit OP growth, depending on the circumstances. This review delineates some of these circumstances and informs future research and guidance towards effective deployment of pipe materials for control of OPs.

show abstract

Residential water heater cleaning and occurrence of Legionella in Flint, MI

Cited by 17 publications

References 37 publications

Considerations for large building water quality after extended stagnation

Considerations for large building water quality after extended stagnation

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

Critical Review: Propensity of Premise Plumbing Pipe Materials to Enhance or Diminish Growth of Legionella and Other Opportunistic Pathogens

Contact Info

Product

Resources

About