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Groundwater provides 40–60% of California's water supply. However, domestic wellwater quality is not regulated in California due to its decentralized nature and high cost oftesting. Many well water users rely on regional groundwater monitoring data (e.g. GroundwaterAmbient Monitoring and Assessment) for information about their water quality but there remainsa need for an integrated approach that combines place-based quantitative analysis with cancerrisk assessment and community engagement. Our pilot study aims to build relationships andscience literacy with private well water users through compensated community sampling ofCalifornia well water and provision of quantitative reports including 22 inorganic constituents(e.g. lead, arsenic, nitrate) with primary and secondary MCLs. Additionally, the pilot study seeksto investigate the impacts of seasonality, land use, and climate change phenomena (e.g. wildfire,drought, floods) on well water quality. Participants (n=113) were recruited in collaboration withour community partner, the Environmental Justice Coalition for Water. Chemical analyses wereperformed at UC Davis and used to generate water quality reports and to assess potential publichealth risks and resources for remediation (see Figure A6 in Appendix). Of the 113 well samplestested, 14 (12.4%) had at least one constituent exceedance of Primary Maximum ContaminantLevels (MCLs), 74 (64.5%) had at least one constituent exceedance of Secondary MCLs, and allhad at least one constituent exceedance of Public Health Goals (PHGs) and Notification Levels(NLs) (e.g. Lead (57/57), Uranium (28/57), Arsenic (12/57), Cadmium (11/57)). This study willhelp study participants assess the health risks associated with consumption of their well waterand provides the infrastructure to scale up to a larger community-based groundwater qualitymonitoring program.

In many developing countries, poorly constructed pit latrines are the primary source of groundwater contamination. Approaches are needed to identify site-specific separation distances between domestic wells and pit latrines. In this study, tracer transport simulations are combined with water quality monitoring data to identify separation distances in peri-urban Dar es Salaam. Bivariate correlation and linear regression models were used to find the relationships between (1) simulated tracer and distances from the wells to the nearest pit latrines (2) simulated tracer and observed contaminants (nitrate, E. coli, and total dissolved solids). The results showed a strong correlation between tracer with nitrate and E. coli, with Pearson coefficient (r) values of 0.80 and 0.79, but a weak correlation with total dissolved solids (TDS) (r = 0.23). A strong correlation between tracer and distance for shallow and deep wells (r = −0.96, −0.76) was found. Based on the soil type and aquifer properties in the area, wells must be placed at least 34 m from a pit latrine to minimize contamination. With recent advances in sensor technologies and the availability of low-cost sensors, linking simulated tracer with observed contaminant levels may provide an alternative first approach to quickly assess human health risks associated with groundwater contamination. HIGHLIGHTS A method to determine site-specific separation distance between wells and pit latrines was developed.; Tracer transport simulations and statistical analyses were used to find relationships between tracer, distance and contaminants.; A strong correlation was found between simulated tracer, distance to the nearest pit latrine and contaminants.; In this area, wells must be placed >34 m from pit latrines to minimize contamination.

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.

Groundwater is a critical water resource in many peri-urban areas without municipal water supply, a common situation globally, but especially in Africa. These areas contain multiple water pollution risks from various human activities, including small industry, dumping, stock and pet animals, and pit latrines. Stinkwater village, 40 km north of Pretoria in Gauteng Province, that has only partial municipal water supply, was sampled for water quality from municipal taps, boreholes and open hand-dug wells. The water quality varied greatly, with few obvious geographic or geochemical correlations, other than high bacterial counts in the open wells. The key health concerns were nitrate, fluoride and coliform bacteria (including E. coli ), some at dangerous levels. Relatively subtle variations in land use, including water use and pollution sources, as well as vadose zone character, including depth to water table, permeability and recharge pathways, could account for much of the variation in water quality. The study reveals the risk of relying upon a single water quality analysis to determine groundwater conditions for an area. In areas with multiple possible pollution sources, thorough groundwater monitoring is needed to determine the usability of water resources. Keywords: groundwater, domestic wells, pit latrines, contamination, urban areas

Study region: California, USA. Study focus: Identification of groundwater use is an important step in the regional-scale assessment of groundwater quality. In California, 1990 US Census data indicate that domestic wells provide drinking-water to about 1.2 million people. However, the location of these domestic well users of groundwater is poorly identified because the census tracts can be quite large (up to 20,000 km2). The purposes of this paper are to present methods used for (1) estimating the location of domestic wells, (2) estimating the location of households using domestic well water; and (3) identifying where in California groundwater is an important source of domestic drinking supply. New hydrological insights for the region: Aggregating the results indicates that three hydrogeologic provinces contain nearly 80% of all domestic wells and also have the highest density of domestic well users: Central Valley (31.6%), Sierra Nevada (31.5%), and Northern Coast Ranges (16.6%). Results were also aggregated into groundwater basins and highland areas, collectively called Groundwater Units (GUs). Twenty-eight of the 938 GUs contain more than 50% of the total population served by domestic wells, 70 GUs contain more than 75%, and 150 GUs contain 90%. The 28 GUs are mostly located in the eastern and southern San Joaquin Valley (11), the Sacramento Valley (7), and the western foothills of the Sierra Nevada province (5). Using the information presented in this research along with other information about domestic-well use, the US Geological Survey has begun sampling high-use GUs for the Shallow Aquifer Assessment component of the Groundwater Ambient Assessment (GAMA) program. Keywords: Domestic wells, Drinking water, Groundwater, Statistical sampling, Hydrogeologic province, California

Urban sanitation remains a significant challenge for most low- and middle-income countries. While sanitation coverage has been increasing across both the 48 least developed countries (LDCs) and developing regions as a whole, progress has been relatively slow. In many cities, even where improved on-site facilities are used to contain excreta, the level of quality and access to services for the emptying, conveyance, treatment, and disposal of the resulting fecal sludge is usually limited. These services are collectively called fecal sludge management (FSM) services. FSM services are the focus of this study, within the broader context of urban sanitation and integrated urban water management (IUWM). This document provides a summary of the diagnostic tools developed for assessing FSM services and is based on field work carried out in the five cities of Balikpapan in Indonesia, Dhaka in Bangladesh, Hawassa in Ethiopia, Lima in Peru, and Santa Cruz in Bolivia. It summarizes the tools themselves, lessons learnt about their use, and general policy recommendations.

The purpose of this report was to investigate the general water quality from domestic wells within the municipality of Torsås. The purpose was also to investigate the spatial and temporal variation of the water quality, including comparisons with other regions in Sweden. The results are based on 771 samples from domestic wells. The results from this survey showed that 84 % of the water samples had deficient water quality and 25 % of the samples showed that the water should not be used as drinking water. This proportion was significantly higher than in a national survey, most probably related to the higher proportion of dug well in Torsås in comparison to other regions in Sweden. The water quality data from domestic wells did not show any significant long-term (2004-2015) change in Torsås. There were spatial differences of the water quality within the municipality. The water quality in the inland regions had in general a better water quality than drinking water along the coastal areas. Drinking water originating from domestic wells located closest to the land-use category coniferous forest had better water quality than drinking water originating from domestic wells located closest to the land-use category deciduous forest and cultivations field. The conclusion is that there is a high proportion of deficient water and that the water quality in Torsås is more deficient than other regions in Sweden. There is also a spatial variation in water quality within the municipality.

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 μg/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.

The 1987 pesticide monitoring program was a continuation of pesticide monitoring of domestic and municipal wells located in hydrogeological environments which are sensitive to groundwater contamination; namely shallow groundwater conditions in sandy permeable soils. Monitoring was conducted in predominantly corn growing areas since corn herbicides are the group of pesticides which are used in the greatest amount in Ontario. As well, an area of intense market gardening, the Thedford Marsh was also included in the 1987 survey. A total of 41 domestic wells and 1 municipal well were sampled weekly for pesticides and bacteria and weekly or monthly for major ion chemistry in Southeastern, Central and Southwestern Regions of the province. Pesticides of interest included the triazine group and the acetanilide group. In Southwestern Region organophosphate and chlorophenoxy group pesticides were analyzed in samples from Thedford Marsh area, and samples from the Bowmanville area of Central Region were also analysed for chlorophenoxy pesticides. The results indicated that detectable levels of pesticides were found in 6 of 23 wells from Southwestern Region, none of 11 wells from Central Region and 8 of 8 wells from Southeastern Region. Eighty-eight per cent of the 108 pesticide occurrences reported were for atrazine and/or d-ethyl atrazine, 7% for cyanazine, 4% for metolachlor and 1% for simazine. Concentrations for atrazine were all below 1.5 ppb. which is considerably below the Interim Maximum Acceptable Concentration (IMAC) of 60 ppb set by the Federal-Provincial Subcommittee on Drinking Water and reported in the Guidelines for Canadian Drinking Water Quality. Concentrations of cyanazine, metolachlor and simazine were all below 1.0 ppb, and their respective IMAC's of 10, 50 and 10 ppb. Persistent but low level pesticide occurrence in wells in the Frankford area of Southeastern Region, including the Frankford municipal well indicate the sensitivity of this aquifer to land use. Sixty-six percent of all the wells sampled also exceeded provincial drinking water quality objectives for nitrate-nitrogen and/or fecal coliform. The results of this program indicate that shallow domestic wells and shallow groundwater are susceptible to contamination and underscore the importance of proper well installation and maintainance, and the protection of groundwater supplies.