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In the United States, people obtain water for household use from one of two sources. Public water systems, which are subject to rules and regulations under the Safe Drinking Water Act, or private sources such as domestic wells, which are not subject to federal regulation and are generally the responsibility of the homeowner or occupant. Public water systems are required to treat their drinking water and conduct regular testing to ensure the delivery of safe water to consumers. From a public health perspective, it is essential to know who is drinking what water to determine risk and impacts from water-borne disease and contamination. We present a new machine-learning approach to estimating water supply source (public or private) at the census block level for the year 2020. While previous studies have largely focused on spatially delineating either public or private water supply, our method incorporates data from both universes, resulting in more accurate modeling results. The utilization of machine learning and additional explanatory data that have not been considered in prior studies results in the most accurate and up-to-date estimate of the count and location of users supplying household water from either a private source or a public water supply. We estimate that 14.1 % of US housing units are supplied by private wells and 84.9 % of housing units are served by a public water system as of 2020., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025. Published by Elsevier Ltd.)

The Drinking Water Tool (DWT) is a community-driven online tool that provides diverse users with information about drinking water sources and threats to drinking water quality and access due to drought. Development of the DWT was guided by the Community Water Center (CWC) as part of the Water Equity Science Shop (WESS), a research partnership integrating elements of community-based participatory research and the European Science Shop model. The WESS engages in scientific projects that inform policy change, advance water justice, and reduce cumulative exposure and disproportionate health burdens among impacted communities in California. WESS researchers conducted qualitative analysis of 15 stakeholder interviews regarding the DWT, including iterative feedback and the stakeholder consultation process as well as stakeholder perceptions of the tool's impact on California water policy, organizing, and research. Results indicate that the DWT and the stakeholder engagement process which developed it were effective in influencing policy priorities and in promoting interagency coordination at multiple levels to address water equity challenges and their disproportionate burdens, particularly among rural and low socioeconomic status areas and communities of color.

Populations in peri-urban communities of Sub-Saharan Africa frequently depend on shallow aquifers and on-site sanitation facilities concurrently. Routinely, domestic wells end up too close to toilet facilities, risking groundwater contamination. For coastal communities, saltwater intrusion adds to the risk of groundwater contamination. This study assessed both risks in five peri-urban communities of Cape Coast, Ghana. Groundwater samples collected from 40 domestic wells were analyzed for physicochemical and microbial constituents. Multivariate statistics including hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to classify and link contaminants to potential sources. Results indicate high enteric bacteria contamination in 98% of the samples, as well as high enrichment in physicochemical constituents, tied largely to impacts of on-site sanitation facilities. We found that wells located within 25 m of septic tanks/toilet facilities contained higher contaminant loads than those without such facilities within 25 m of their locations. Similarly, for wells located close to point sources, the closer the water table is below the land surface (within 2 m), the higher the contaminant loads. Lastly, using molar ratios of Cl - /HCO 3 - and Na + /Cl - with R-mode HCA, the study isolated a few wells, located within 2 km of the coastline, that are experiencing effects of saltwater intrusion. Overall, this study provides useful information for aiding groundwater quality mitigation policy, and the baseline data for aiding future investigations in the study area. It also has broader policy implications for other peri-urban settings throughout Ghana and the entire Sub-Saharan Africa.

Intensive use of antibiotics promotes the occurrence and development of antibiotic resistance. Antibiotic resistance genes (ARGs) enter water environments from human and animal sources. Groundwater serves as an important water supply, while the profiles and risk of ARGs in groundwater remain unknown. The abundance and profiles of ARGs in 11 domestic wells in the Maozhou River basin of Shenzhen City were analyzed by high-throughput qPCR. The results showed that a total of 141 ARGs and 8 mobile genetic elements (MGEs) were detected, of which the genes corresponding resistance to sulfonamides, multidrugs, and aminoglycosides were the most abundant. In each well, the number of detected ARGs and MGEs ranged from 48 to 89, with an average of 68. When normalized by the abundance of 16S rRNA genes, it was found that each bacterium carried at least one ARG in the groundwater of W7, W8, and W10, while in W11, each bacterium carried at least four ARGs. Clinically relevant ARGs that code for resistance to glycopeptide ( blaSHV , blaTEM , blaCTX , and blaOXA-1 ), β -lactams ( vanB and vanC-03 ), or chloramphenicol ( floR ) were found in groundwater. In addition, the abundance of sulfonamides, multidrugs, aminoglycosides, β -lactam, and chloramphenicol resistance genes were positively correlated with the abundance of MGEs ( P <0.01), suggesting that MGEs may promote the spread of ARGs in groundwater.

Purpose of Review: Approximately 12% of the population in the US and Canada rely on federally unregulated private wells, which are common in rural areas and may be susceptible to microbiological and chemical contamination. This review identifies and summarizes recent findings on contaminants of emerging concern in well water across the US and Canada., Recent Findings: Private well water quality modeling is complicated by the substantial variability in contamination sources, well construction, well depth, and the hydrogeology of the environment surrounding the well. Temporal variation in contaminant levels in wells suggests the need for monitoring efforts with greater spatial and temporal coverage. More extensive private well monitoring will help identify wells at greater risk of contamination, and in turn, public health efforts can focus on education and outreach to improve monitoring, maintaining, and treating private wells in these communities. Community interventions need to be coupled with stricter regulations and financing mechanisms that can support and protect private well owners.

While the safety of public drinking water supplies in the Republic of Ireland is governed and monitored at both local and national levels, there are currently no legislative tools in place relating to private supplies. It is therefore paramount that private well owners (and users) be aware of source specifications and potential contamination risks, to ensure adequate water quality. The objective of this study was to investigate the level of awareness among private well owners in the Republic of Ireland, relating to source characterisation and groundwater contamination issues. This was undertaken through interviews with 245 private well owners. Statistical analysis indicates that respondents' source type significantly influences owner awareness, particularly regarding well construction and design parameters. Water treatment, source maintenance and regular water quality testing are considered the three primary "protective actions" (or "stewardship activities") to consumption of contaminated groundwater and were reported as being absent in 64%, 72% and 40% of cases, respectively. Results indicate that the level of awareness exhibited by well users did not significantly affect the likelihood of their source being contaminated (source susceptibility); increased awareness on behalf of well users was associated with increased levels of protective action, particularly among borehole owners. Hence, lower levels of awareness may result in increased contraction of waterborne illnesses where contaminants have entered the well. Accordingly, focused educational strategies to increase awareness among private groundwater users are advocated in the short-term; the development and introdiction of formal legislation is recommended in the long-term, including an integrated programme of well inspections and risk assessments., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: As the population and demand for safe drinking water from domestic wells increase, it is important to examine water quality and contaminant occurrence. A national assessment in 2006 by the U.S. Geological Survey reported findings for 55 volatile organic compounds (VOCs) based on 2,401 domestic wells sampled during 1985-2002., Objectives: We examined the occurrence of individual and multiple VOCs and assessed the potential human-health relevance of VOC concentrations. We also identified hydrogeologic and anthropogenic variables that influence the probability of VOC occurrence., Methods: The domestic well samples were collected at the wellhead before treatment of water and analyzed for 55 VOCs. Results were used to examine VOC occurrence and identify associations of multiple explanatory variables using logistic regression analyses. We used a screening-level assessment to compare VOC concentrations to U.S. Environmental Protection Agency maximum contaminant levels (MCLs) and health-based screening levels., Results: We detected VOCs in 65% of the samples; about one-half of these samples contained VOC mixtures. Frequently detected VOCs included chloroform, toluene, 1,2,4-trimethylbenzene, and perchloroethene. VOC concentrations generally were < 1 microg/L. One or more VOC concentrations were greater than MCLs in 1.2% of samples, including dibromochloropropane, 1,2-dichloropropane, and ethylene dibromide (fumigants); perchloroethene and trichloroethene (solvents); and 1,1-dichloroethene (organic synthesis compound)., Conclusions: Drinking water supplied by domestic wells is vulnerable to low-level VOC contamination. About 1% of samples had concentrations of potential human-health concern. Identifying factors associated with VOC occurrence may aid in understanding the sources, transport, and fate of VOCs in groundwater.