Meteorological Influence on Drinking Water Quality: Microbial Variability in Groundwater Wells and Piped Distribution Networks from Western Romania

TL;DR

This study shows how weather affects drinking water quality in Romania, with groundwater wells being more vulnerable to contamination than piped networks.

Contribution

The study quantifies meteorological influences on microbial contamination in temperate continental climates.

Findings

Groundwater wells are more prone to coliform and E. coli contamination, especially in summer.

Precipitation causes short-term contamination spikes in wells with a 2-day lag.

Piped networks show delayed and weaker responses to weather changes.

Abstract

Climate variability plays a crucial role in shaping drinking water quality, yet the quantitative links between meteorological factors and microbiological contamination remain underexplored in temperate continental climates. A secondary data analysis was conducted on 15,394 microbiological water quality test results collected between 2015 and 2024, including heterotrophic plate counts (22 °C and 37 °C), coliform bacteria, and Escherichia coli, and their associations with local meteorological conditions across groundwater wells and piped distribution networks were examined. A clear distinction emerged: groundwater wells showed higher vulnerability to primary microbial contamination (coliforms and E. coli), whereas distribution networks exhibited higher odds of heterotrophic plate count exceedances, indicating greater susceptibility to post-treatment microbial regrowth. In groundwater wells, temperature showed strong positive associations with all microbial indicators (p < 0.001), with pronounced summer peaks in coliforms and E. coli, while precipitation triggered short-term contamination spikes characterized by a 2-day lag. In contrast, piped networks exhibited weaker and more delayed meteorological responses. These results highlight the need for a shift from climate-responsive to climate-pre-emptive water quality monitoring by incorporating meteorological forecasts, especially for non-chlorinated groundwater sources.

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