The study analyzed 420 tap water samples over a period of six months, starting June 2020.
A recent study evaluated water quality in the plumbing systems of commercial and residential buildings when they were closed for a prolonged time during the COVID-19 pandemic.
The article is a preprint and has not been peer-reviewed, however, states the preprint document detailing the study and its results.
According to the study, the closure of commercial buildings during the pandemic resulted in water stagnation due to reduced flow volumes in their plumbing systems, which led to concerns related to the microbiological safety of drinking water when buildings reopened. To date, the extent of the impact of these closures on water quality remains unknown.
The study analyzed 420 tap water samples over a period of six months, starting June 2020, from sites at three commercial buildings that had reduced capacity and four occupied residential households, reported the preprint article of the research.
Direct and derived flow cytometric measures and water chemistry characterization were used to evaluate the changes in plumbing with extended periods of altered water demand. Some of the parameters assessed included temperature, pH, conductivity, and dissolved oxygen in commercial buildings that were closed for a prolonged time, reported Medical News Today.
According to the results, prolonged building closures impacted microbial communities in commercial buildings, showing increases in microbial cell counts and encompassing a greater proportion of cells with high nucleic acids.
Due to a shift in water demand in these buildings during the pandemic, plumbing systems had reduced flow volumes, leading to water stagnation for about 14 weeks between March and June 2020. The result was deteriorated water quality, which caused microbial regrowth, opportunistic plumbing pathogen (OPP) growth, disinfection byproduct formation, and the leaching of metals, reported Medical News Today.
The metal concentrations were consistently below the regulatory concentrations, however, according to the study.
According to the study, commercial building sites had 39% to 46% lower water demand between March 2020 and May 2020 compared to 2019. Residential sites showed an average of 6% increased water demand during this time compared to 2019.
Ultimately, the results demonstrated that COVID-19-related building closures impacted water demand and the microbial community composition of water in these plumbing systems.