Drinking Water Biofilms: Ecology, Persistence, and Exposure Pathways in Distribution Systems and Premise Plumbing

In natural environments, microorganisms rarely exist as single, dispersed cells. Instead, most exhibit a strong tendency to adsorb onto solid surfaces, rapidly colonizing them in moist conditions and forming species-diverse communities known as biofilms. The genetic diversity of microorganisms in these biofilms, along with the variety of environments they inhabit, forms a key part of their developmental strategy. Heterogeneous microbial populations can coexist, organizing horizontally or vertically depending on the direction of environmental gradients. Microorganisms structured spatially as biofilms show increased resistance to physical and chemical stressors, while gaining numerous metabolic advantages. Adjacent cells — including unrelated ones — can more readily exchange genes, including those associated with antibiotic and disinfectant resistance, via horizontal gene transfer (HGT). Uncontrolled biofilm formation with random, pathogenic compositions can have serious negative consequences for municipal utilities and contribute to the spread of hard-to-treat infections. Saprophytic, pathogenic, and opportunistic pathogens can spread through surface and groundwater, drinking water distribution systems, sewage and sewer networks, and heating systems. In particular, drinking water distribution systems and premise plumbing can act as reservoirs and exposure pathways for opportunistic and emerging bacterial threats not routinely captured by standard water quality monitoring.

The lack of biological and chemical stability in water entering municipal distribution systems promotes secondary microbial growth, leading to biofilm formation on the internal surfaces of water pipes. Consequently, water quality at the consumer end often differs from that at the entry point to the supply network due to secondary contamination within the distribution system. As a vital abiotic environmental component, water must be safe for human health: free of pathogenic microorganisms and parasites at levels posing a health risk, devoid of chemicals in quantities that endanger health, and exhibiting limited corrosive properties.

This Research Topic aims to investigate the ecological, microbiological, genetic, and molecular mechanisms underlying biofilm formation, persistence, and bacterial transmission in drinking water distribution systems and premise plumbing. Particular emphasis will be placed on how complex microbiomes interact to influence biofilm development, cell-cell interactions, pathogenicity, and antimicrobial resistance. Special attention will also be given to bacterial survival under disinfection stress, persistence in engineered water systems, and exposure pathways relevant to human health. These findings should contribute to developing methods for monitoring and mitigating the impacts of these microbial communities on aquatic environments and public health.

We encourage authors to submit original research, reviews, and perspectives on, but not limited to, the following topics:

- The transmission of opportunistic pathogenic microorganisms through water distribution systems, especially those not included in routine water quality monitoring. These microorganisms may act as etiological agents in infections among water users, particularly in the context of dormant, non-dividing VBNC (viable but non-culturable) bacterial cells and other persistent bacterial states relevant to emerging threats.

- The molecular mechanisms underlying biofilm formation on the construction materials of municipal water pipes, including the role of key physicochemical parameters (such as flow velocity, pH, temperature, and surface properties) within the pipeline environment and premise plumbing systems.

- The complexity of intra- and interspecies interactions within biofilms, with particular emphasis on molecular signals regulating microbial communication (quorum sensing, QS). This includes the influence of such signaling on virulence, increased resistance to external stressors (including antibiotics and disinfectants), and the potential formation of multidrug-resistant persister cells in response to signaling molecules.

- The feasibility of developing biosensors capable of detecting microbial cell adhesion on the inner surfaces of water pipes and enabling real-time measurements. Such biosensors could contribute to the modernization and optimization of monitoring infrastructure in the municipal water industry and support early warning approaches for bacterial contamination.

- The development and implementation of effective, modern strategies for combating biofilms, including methods aimed at inhibiting their growth and preventing their formation. Examples include approaches that target mechanisms disrupting microbial communication (e.g., quorum-sensing inhibition) or other biofilm-specific pathways, as well as strategies to reduce exposure to biofilm-associated opportunistic and antibiotic-resistant bacteria.

If you are interested in submitting or have any questions, please contact the journal email: bacteriology@frontiersin.org.

Article types and fees

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Case Report
• Classification
• Clinical Trial
• Editorial
• FAIR² Data
• General Commentary
• Hypothesis and Theory
• Methods
• ... View all formats

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Article types

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Case Report
• Classification
• Clinical Trial
• Editorial
• FAIR² Data
• General Commentary
• Hypothesis and Theory
• Methods
• Mini Review
• Opinion
• Original Research
• Perspective
• Review
• Systematic Review
• Technology and Code

Keywords: drinking water, water distribution systems, premise plumbing, biofilms, horizontal gene transfer, quorum sensing, opportunistic pathogens, antimicrobial resistance, water safety, One Health

Important note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.