{ "abstract": "Over 43 million individuals in the United States use private wells for drinking water, but these wells are not regulated by the Safe Drinking Water Act. Unmaintained private wells on farms could become contaminated from pathogens from various potential sources including on-farm animal waste. Microbial contaminants in private wells could increase infectious disease risks among well users, therefore it is important to conduct well water testing and keep a well maintained system. We distributed surveys and collected water samples from private wells that supply drinking water on farms from all seven regions of Maryland. Our objective was to evaluate the presence of total coliforms and E. coli in private wells and the impact of well, geographic, and precipitation factors on the bacterial contamination risk. Eighty-four water samples were collected from 79 private wells on farms across Maryland. Samples were analyzed for total coliforms and E. coli with U.S. EPA Method 1604. Data were analyzed using Fisher’s Exact test and logistic regression. Forty-three percent (34/79) of the sampled wells were positive for total coliforms and 10% (8/79) were positive for E. coli. Total coliform presence was significantly associated with county (p = 0.02), region (p < 0.01), and well condition description (p = 0.02). E. coli presence was significantly associated with region (p < 0.01), geological province type (p < 0.01), county (p = 0.04), and wellhead cover type (p = 0.03). Based on the multivariable logistic regression, wells that were described as being in okay or fair condition had significantly lower odds of total coliforms compared to wells described as being in good or excellent condition (p = 0.03), suggesting a lack of understanding about actual well conditions. There was a significant decrease in the odds of E. coli presence as precipitation levels 14 days prior to sampling increased (p = 0.02). These results emphasize the importance of private well water testing, particularly for farmers.", "abstract_shown": true, "affiliations": [ "Department of Global, Environmental, and Occupational Health, University of Maryland School of Public Health, College Park, Maryland, United States of America", "Maryland Agriculture Experiment Station, University of Maryland, Maryland, United States of America", "Maryland Extension, University of Maryland, Maryland, United States of America", "Department of Epidemiology and Biostatistics, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, United States of America" ], "article_type": "Research Article", "arxiv": null, "author_total": 15, "authors": [ { "affs": [ 0 ], "name": "Cameron Smith" }, { "affs": [ 1 ], "name": "Emily M. H. Woerner" }, { "affs": [ 2 ], "name": "Alan Leslie" }, { "affs": [ 3 ], "name": "Benjamin Beale" }, { "name": "Kelly Nichols" }, { "name": "Shannon Dill" }, { "name": "Sarah Hirsh" }, { "name": "Jeff Semler" }, { "name": "Andrew Kness" }, { "name": "Jack Keane" }, { "name": "Marina Costa" }, { "name": "Julie Yang" }, { "name": "Raul Cruz-Cano" }, { "name": "Andrew Lazur" }, { "name": "Rachel Rosenberg Goldstein" } ], "bibtex": "https://research.draconitic.com/paper/18330q8ngy60p.bib", "cited_by": 0, "doi": "10.1371/journal.pwat.0000636", "fulltext_url": "https://journals.plos.org/water/article?id=10.1371/journal.pwat.0000636", "id": "18330q8ngy60p", "issns": [ "2767-3219" ], "landing_url": "https://journals.plos.org/water/article?id=10.1371/journal.pwat.0000636", "language": null, "licence": "CC-BY-4.0", "licence_label": "CC BY 4.0", "licence_source": "journal", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "openalex", "2312|Fecal contamination and water quality" ], [ "plos", "/Biology and life sciences/Microbiology/Medical microbiology/Microbial pathogens/Bacterial pathogens/Escherichia coli" ], [ "plos", "/Biology and life sciences/Organisms/Bacteria/Enterobacteriaceae/Escherichia/Escherichia coli" ], [ "plos", "/Biology and life sciences/Organisms/Bacteria/Gut bacteria/Escherichia/Escherichia coli" ], [ "plos", "/Earth sciences/Geography" ], [ "plos", "/Earth sciences/Geology" ], [ "plos", "/Ecology and environmental sciences/Natural resources/Water resources" ], [ "plos", "/Ecology and environmental sciences/Water quality" ], [ "plos", "/Medicine and health sciences/Epidemiology/Medical risk factors" ], [ "plos", "/Medicine and health sciences/Pathology and laboratory medicine/Pathogens/Microbial pathogens/Bacterial pathogens/Escherichia coli" ], [ "plos", "/People and places/Geographical locations/North America/United States/Maryland" ], [ "plos", "/Research and analysis methods/Animal studies/Experimental organism systems/Model organisms/Escherichia coli" ], [ "plos", "/Research and analysis methods/Animal studies/Experimental organism systems/Prokaryotic models/Escherichia coli" ], [ "plos", "/Research and analysis methods/Model organisms/Escherichia coli" ], [ "plos", "/Research and analysis methods/Research design/Survey research/Surveys" ] ], "openalex": "W7214911331", "pdf_url": "https://journals.plos.org/water/article/file?id=10.1371/journal.pwat.0000636&type=printable", "pmcid": null, "pmid": null, "published": "2026-09-30", "publisher": "Public Library of Science", "ris": "https://research.draconitic.com/paper/18330q8ngy60p.ris", "sources": [ { "first_seen": "2026-10-30T12:17:37Z", "native_id": "10.1371/journal.pwat.0000636", "source": "plos", "url": "https://journals.plos.org/water/article?id=10.1371/journal.pwat.0000636" } ], "subjects": [ { "field": "biology", "origin": "plos:microbiology", "subfield": "microbiology" }, { "field": "earth", "origin": "plos:geology", "subfield": "geology-geochemistry" }, { "field": "medicine", "origin": "plos:epidemiology", "subfield": "epidemiology-public-health" } ], "title": "E. coli and total coliform presence in private drinking water wells on Maryland farms: Determination of the impact of well properties, geographic, and precipitation factors", "title_text": "E. coli and total coliform presence in private drinking water wells on Maryland farms: Determination of the impact of well properties, geographic, and precipitation factors", "type": "peer-reviewed", "updated_at": "2026-10-30T12:17:37Z", "url": "https://research.draconitic.com/paper/18330q8ngy60p", "venue": "PLOS Water", "versions": [] }