Impacts of household water demands and water heater delivery temperatures on opportunistic premise plumbing pathogens (OPPPs) in a residential setting

Published

February 1, 2025

Author(s)

Alshae Logan, Jumana Aljafari, Visesh Uppoor, Tania Ullah, Jennifer Dootz

Abstract

Efforts aimed towards water and energy conservation within residential buildings may create enhanced conditions for Opportunistic Premise Plumbing Pathogens (OPPPs) growth. To investigate this issue, a study was conducted to assess the effect of water demands and water temperature on four OPPPs – L. pneumophila, P. aeruginosa, M. avium, and N. fowleri – in a residential test facility. Two water delivery temperatures (54 and 66 °C) and household water demands (low: 47.3 or 127.9 L; high: 263.1 L) were evaluated. A total of 260 samples were collected and analyzed using droplet digital polymerase chain reaction (ddPCR). Samples were collected from the influent water pipe, water heater, PEX manifold, kitchen and bathroom faucets, tub, and shower. The most frequently detected OPPP was L. pneumophila, which was found in 8.1 % of water samples, followed by P. aeruginosa (3.5 %), and M. avium (1.9 %). Water demand and water heater setpoint temperature were independently associated with the detection and concentration of L. pneumophila. Kitchen and bathroom faucets posed a higher risk of exposure to L. pneumophila compared to the tub and shower. The current dataset represents the largest-scale investigation to date of the effect of household operating conditions on OPPPs. This dataset can be used in quantitative microbial risk assessment (QMRA) models to estimate the potential risk of infection with OPPPs.

Citation

Total Environment Microbiology

Volume

1

Issue

1

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.temicr.2025.100002

Local Download

Keywords

Household water demands, Water heater temperature, Opportunistic premise plumbing pathogens (OPPPs), Legionella pneumophila, PEX manifold

Citation

Logan, A. , Aljafari, J. , Uppoor, V. , Ullah, T. and Dootz, J. (2025), Impacts of household water demands and water heater delivery temperatures on opportunistic premise plumbing pathogens (OPPPs) in a residential setting, Total Environment Microbiology, [online], https://doi.org/10.1016/j.temicr.2025.100002, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934931 (Accessed April 12, 2025)