Small Water Systems Research Articles

Biological ion exchange for natural organic matter removal from drinking water.

Water is a precious resource, and effective management is crucial for utilities of all sizes. However, small water systems often face unique challenges when controlling water loss.

Arsenic in drinking water poses a threat to public health world-wide. In March 2001, the EPA revised the maximum contaminant level (MCL) for arsenic in drinking water downward from 50 µg/L to 10 µg/L and required all U.S. small community water systems (CWSs) and non-community water systems (NCWSs) to comply by 23 January 2006. Much of the financial burden associated with complying with and maintaining this new drinking water MCL was shouldered by local community governments. For example, the Walker River Paiute Tribe operated a CWS on the Walker River Paiute Indian Reservation that needed upgrading to meet the new arsenic MCL. In collaboration with the Walker River Paiute Tribe, we conducted a study to assess whether reducing the arsenic concentration in drinking water to meet the new MCL reduced the arsenic body burden in local community members who drank the water. Installing a drinking water treatment to remove arsenic dramatically reduced both the drinking water concentrations (to below the current EPA MCL of 10 µg/L) and the community members’ urinary concentrations of total As, AsIII, and AsV within a week of its full implementation. Additional assistance to small water systems to sustain new drinking water treatments may be warranted.

The mission of AWWA's Small Systems Division (SSD) is to help small communities develop the technical, managerial, and financial capabilities to sustainably manage water services. The SSD invites small water system staff to take advantage of the full slate of valuable technical sessions at AWWA's 2025 Annual Conference & Exposition (ACE25), which will be held June 8–11 in Denver.

Abstract Very small drinking water systems in the United States can face challenges in complying with the Safe Drinking Water Act, resulting in a need to improve existing infrastructure. This study applied a triple bottom-line approach to compare modeled health, environmental, and economic impacts of improving existing centralized water treatment systems to using point-of-use/point-of-entry (POU/POE) devices in four very small community water systems (CWS) serving 40–450 people. We found that POU/POE systems could be implemented 1–3 years faster than centralized improvements and achieve higher removal efficiencies (up to 99% removal for arsenic, compared to 80% for some centralized options), resulting in larger decreases in human exposure to arsenic or nitrate. Treatment options using adsorptive media or ion exchange resins had larger overall environmental impacts than reverse osmosis devices, and the total 30 year cost of POUs/POEs were more expensive in 3 of the 4 modeled systems than centralized improvements due to high replacement frequencies and populations. An ‘ideal’ option in each CWS was not selected; rather, we contextualized our results as tradeoffs.

Efficacy of UVC-LED radiation in bacterial, viral, and protozoan inactivation: an assessment of the influence of exposure doses and water quality

Water is a critical resource for human life and plays a vital role in energy production. Energy is equally essential in water supplies but generates carbon emissions to the atmosphere depending on the energy source. Appraising water, energy, and carbon nexus is essential for promoting sustainable drinking water systems (DWSs) in the case of small- and medium-sized utilities, representing a significant portion of the water supply in many countries. Smaller utilities face unique challenges, such as insufficient funding, aging infrastructure, and higher operational costs. This paper examines over 100 studies to identify and comprehensively understand how source type and location, raw water quality, water consumption patterns, system size, land use, population density, topography, infrastructure age, and system losses and maintenance impact energy consumption in small and medium DWSs. The review also identified more than 40 indicators related to energy and carbon from the literature, providing advanced information in this area. Findings suggest a gap in understanding how energy and carbon indicators relate to the utility's operational performance. By analyzing the challenges and opportunities smaller utilities face in optimizing water, energy, and carbon nexus, this paper highlights the necessity of shifting towards cleaner energy sources to mitigate the environmental impacts. It also emphasizes the importance of adopting a holistic approach that integrates technological advancements, regulatory guidelines, and active community engagement to achieve decarbonization in DWSs. The present study aims to inform policymakers, water management professionals, and broader stakeholders about the essential components of sustainable and resilient small and medium DWSs.

Supplying water to cities is an energy-intensive activity, but few longitudinal studies exist of water utilities’ energy intensity (energy use per unit water volume). Using t-tests and regression on public records from the state of Wisconsin, USA, we analyze over 500 drinking water utilities’ performance from 2001 to 2020. This is the first long-term panel analysis of its kind. The annual data show energy intensity has increased by 12 % in large, 8 % in medium, and 28 % in small water utilities. The large utilities remain the least energy intensive (0.49 kWh/m³ as of 2020, compared to 0.53 kWh/m³ and 0.67 kWh/m³ for medium and small utilities), and the small ones have diverged the most from the other two. At the same trajectory, energy intensity will increase by another 27 % for small water systems by 2040. Our analysis demonstrates economies of scale, highlights disadvantages of small utilities, and confirms predictions that water services would become more energy intensive. It motivates sustainability of coupled energy and water infrastructure and emphasizes responsible use of natural resources.

Abstract In the United States, most residents receive water from centralized utilities regulated under the federal Safe Drinking Water Act. Yet, a sizable portion of U.S. residents satisfy their household water needs through decentralized means, including domestic wells, very small water systems, and hauled water. These federally unregulated water users are among the most vulnerable to the impacts of climate change, particularly in aridifying regions like the Southwest. They are, however, inconsistently monitored and regulated at the Tribal, federal, state, and local levels. Compared to regulated users, very few programs exist to assist this population in securing and maintaining safe, affordable drinking water access. This neglect creates a vicious cycle whereby their water security needs remain both poorly understood and inadequately addressed. We review available data sources, regulations, assistance programs, and published studies relevant to unregulated water users across the Southwestern U.S. to illustrate this injurious feedback loop. We then propose four key areas for intervention to transform this vicious cycle into a virtuous one. Drawing on new insights from the emerging literature on modular, adaptive, and decentralized (MAD) water infrastructure, we highlight opportunities for investment and innovation to support decentralized service alongside existing investments in centralized infrastructure, and the critical need to attend to justice in the design and implementation of such policies.This article is categorized under: Science of Water > Water and Environmental Change Human Water > Water Governance Human Water > Rights to Water

AWWA's Small Systems Division helps small communities develop the technical, managerial, and financial capabilities to sustainably manage water services. The division invites small water system staff to take advantage of the full slate of valuable technical sessions at AWWA's 2024 Annual Conference & Exposition (ACE24), which will be held June 10‐13 in Anaheim, Calif.

For small public water systems, vulnerability to cyberattacks is a serious concern. This is especially true for systems operating on a low budget for upgrading outdated information technology equipment and cybersecurity plans.

Community-based water tenure in equitable and transformative drought resilience

Improving water quality, small public water systems, and safe drinking water (EPA)

Abstract Scholars and policy makers alike frequently promote drinking water system consolidation as a solution to the longstanding struggles of small water systems and the related consequences of service fragmentation, including vulnerability to climate change and persistent racial and economic inequalities in access to safe and affordable drinking water. Despite enthusiasm for the concept, however, our understanding of how, why, and where consolidations occur has remained stubbornly limited such that the promise of drinking water system consolidation remains theoretical at best. This study analyzes all known water system consolidations (n = 206) in the state of California over a 7‐year period (2015–2021). We find empirical support for certain theoretical claims about consolidation, including an overall reduction in the number of regulated systems, with the largest reductions occurring among particularly underperforming, climate‐vulnerable, and unrepresentative system types. Other findings, however, do not align with the literature on the subject. We find limited evidence of either water service privatization or remunicipalization trends and seemingly limited prospects for economies of scale benefits through consolidations. Moreover, roughly half of consolidations during the study period involve non‐residential water systems. Among the consolidated community water systems, systems serving higher‐resourced communities are overrepresented compared to those serving lower‐resourced communities by a margin of two‐to‐one. It is time to move beyond the blanket assumption of positive consolidation benefits toward a more nuanced understanding of the associated opportunities and limitations. Depending on their goals, policymakers may need to support more specific types of consolidation.

Motivating the formation of partnerships by small water systems

Existing heterotrophic denitrification reactors rely on microorganisms to consume dissolved oxygen (DO) and create conditions suitable for denitrification, but this practice leads to excessive microbial growth and increased organic carbon doses. An innovative reactor that uses nitrogen gas sparging through a contactor to strip DO was developed and tested in the lab. It reduced influent nitrate from 15 to <1 mg/L as N with nitrite accumulation <1 mg/L as N. It maintained a consistent flow rate and developed minimal headloss, making it easier to operate than the denitrifying dual-media filter that was operated in parallel. Gravel, polyvinyl chloride pieces, and no packing media were assessed as options for the nitrogen-sparged contactor, and gravel was found to support denitrification at the highest loading rate and was resilient to nitrogen-sparging shutoffs and intermittent operation. This innovative reactor appears promising for small drinking water systems.

Centralized water infrastructure has, over the last century, brought safe and reliable drinking water to much of the world. But climate change, combined with aging and underfunding, is increasingly testing the limits of-and reversing gains made by-these large-scale water systems. To address these growing strains and gaps, we must assess and advance alternatives to centralized water provision and sanitation. The water literature is rife with examples of systems that are neither centralized nor networked, but still meet water needs of local communities in important ways, including: informal and hybrid water systems, decentralized water provision, community-based water management, small drinking water systems, point-of-use treatment, small-scale water vendors, and packaged water. Our work builds on these literatures by proposing a convergence approach that can integrate and explore the benefits and challenges of modular, adaptive, and decentralized ("MAD") water provision and sanitation, often foregrounding important advances in engineering technology. We further provide frameworks to evaluate justice, economic feasibility, governance, human health, and environmental sustainability as key parameters of MAD water system performance.

ABSTRACT Performance assessment of Small and Medium-Sized Water Systems (SMWSs) is important for operational, tactical, and strategic decision-making. In this study, a performance assessment method has been developed and applied to five drinking water, three wastewater, and two stormwater utilities using 39, 30 and 27 Key Performance Indicators (KPIs) in a semi-arid region. The KPIs were aggregated to determine a performance index using a Technique for Order of Preference by Similarity to Ideal Solution method. K-nearest neighbors and penalty methods were used to estimate missing KPIs data. The results indicated that only two drinking water utilities and one wastewater utility had been rated as ‘high’ performance. None of the utilities in stormwater performance was rated as ‘high’. The developed method can assist decision-makers in evaluating SMWSs performance holistically, build operational management strategies, and identify necessary interventions in overcoming water systems challenges across each urban water system component.

Manganese (Mn) is currently regulated as a secondary contaminant in California, USA; however, recent revisions of the World Health Organization drinking water guidelines have increased regulatory attention of Mn in drinking water due to increasing reports of neurotoxic effects in infants and children. In this study, Mn concentrations reported to California's Safe Drinking Water Information System were used to estimate the potentially exposed population within California based on system size. We estimate that between 2011 and 2021, over 525,000 users in areas with reported Mn data are potentially exposed to Mn concentrations exceeding the WHO health-based guideline (80 μg L-1), and over 34,000 users are potentially exposed to Mn concentrations exceeding the U.S. Environmental Protection Agency health-advisory limit (300 μg L-1). Water treatment significantly decreased Mn concentrations compared to intake concentrations for all system sizes. However, smaller water systems have a wider range and a higher skew of Mn concentrations in finished water than larger systems. Additionally, higher Mn concentrations were found in systems above the maximum contaminant levels for chromium and arsenic. The treatment of these primary contaminants appears to also remove Mn. Lastly, data missingness remains a barrier to accurately assess public exposure to Mn in very small, small, and medium community water system-delivered water.

Pilot study on arsenic removal from phosphate rich groundwater by in-line coagulation and adsorption