Multi-scale geospatial assessment of water reuse potential in the contiguous U.S.

Abstract

Integrated water resources management faces significant challenges due to water scarcity and declining water quality. In the context of growing global water demand, efficient management and reuse have become essential for maintaining adequate supplies and ensuring sustainability. Consequently, access to accurate data and advanced tools is vital for informed decision-making in water reuse strategies. This study addresses this need by developing a water inventory for the contiguous U.S. and an interactive application with advanced visualization tools to analyze water availability across multiple spatial scales. The inventory categorizes water into two traditional sources (surface runoff and recharge) and four sources for reuse (rainwater, stormwater, treated wastewater, and agricultural runoff). Multiple reanalysis datasets and geospatial databases were utilized to estimate water volumes, covering 48 states, 3,108 counties, and 31,099 communities (incorporated and unincorporated). The WaterWise application allows users to interactively analyze water availability, generating charts of water volumes by source and aggregating data at community, county, state, and watershed levels. This work demonstrates that water reuse is a sustainable solution to U.S. water scarcity: favorable climate conditions in the eastern U.S. make water reuse highly feasible, while in the west, strategies must be adapted regionally to optimize available resources and enhance resilience to future water challenges.

1 Introduction

Water reuse is increasingly recognized as an important strategy for addressing global water scarcity, driven by population growth and climate change. By 2030, global demand for freshwater is expected to exceed supply by 40%, potentially leading to a global water crisis if urgent measures are not taken (United Nations Educational Scientific and Cultural Organization, 2021). Currently, over 2 billion people live in countries experiencing water stress, and it is estimated that 4 billion people face severe physical water scarcity for at least 1 month each year (Biswas et al., 2025). Water scarcity occurs when the demand for water exceeds the available supply during a certain period or when the quality of water is inadequate for its intended use (Stets et al., 2025). Water reuse has emerged as a viable solution in response to this growing challenge. The U.S. Fifth National Climate Assessment report identifies water reuse as one of the available options to protect water supplies (USGCRP, 2023).

The history of water reuse in the U.S. is multifaceted and reflects the evolution of water management practices in response to increasing water scarcity, technological advancements, and shifts in public perception. Historically, the practice of water reuse can be traced back thousands of years, with ancient civilizations employing various methods to recycle water for agricultural and domestic uses (Angelakis et al., 2018). In the modern context, the U.S. has developed a structured approach to water reuse characterized by state-specific regulations and guidelines. Eleven states have recently established water reclamation frameworks, with California, Arizona, Texas, and Florida being pioneers in implementing these programs (Ramm and Smol, 2023). These regulations are crucial as they dictate the standards for treatment processes and the acceptable uses of reclaimed water, ranging from irrigation to potable applications (Reddy et al., 2023).

The concept of water reuse in U.S. communities incorporates multiple practices, including recycling wastewater for non-potable uses such as irrigation and industrial processes and even potable applications, thereby alleviating pressure on freshwater resources and improving sustainability (EPA, 2024). These practices are a viable strategy to reduce the water footprint of communities. Water reuse helps reduce the demand for freshwater by using treated effluent, thus conserving potable water for essential uses such as drinking, cooking, and personal hygiene (EPA, 2024). Furthermore, implementing water reuse systems has the potential to reduce the volume of wastewater discharged into natural water bodies, which may help lower pollution levels and contribute to improved overall water quality (Frijns et al., 2016).

Technological innovations have played an essential role in optimizing water reuse in U.S. communities, especially in wastewater treatment. Innovations have enabled the production of high-quality reclaimed water suitable for various applications, including agricultural irrigation and potable reuse (Org et al., 2015; Shoushtarian and Negahban-Azar, 2020). However, despite these advancements, public perception remains a critical barrier to the widespread adoption of water reuse practices. Studies show that acceptance of water reuse decreases as the perceived closeness to human consumption increases, highlighting the need to address psychological factors in promoting such initiatives (Singha and Eljamal, 2022). It is vital to tackle the information accessibility gap in communities to foster greater adoption of water reuse practices. Although extensive research has explored various aspects of water reuse, there is still no national, multi-scale tool that consolidates and regularly updates all relevant data to effectively support its implementation. We hypothesize that combining open datasets at the community scale can reveal spatial differences in water reuse potential and help identify areas where interventions would be most effective. This idea guided the development of the WaterWise application, an interactive platform built to provide a comprehensive water inventory for the contiguous U.S. and allow users to assess water availability across multiple scales. The tool provides detailed data on traditional water sources (such as surface runoff and recharge) and volumes of water available for reuse. It is specifically designed for small communities facing significant economic and technological barriers, enabling them to assess better, plan, and implement water reuse strategies based on local and regional conditions. This study synthesizes existing datasets, the primary innovation lies in the integration of these data into a multi-scale, publicly accessible tool that enables community-specific analysis and supports decision-making for water reuse strategies.

This manuscript introduces an interactive application designed to support decision-making by providing detailed information on water volumes available for reuse. Our study aims to enhance awareness about water reuse and quantify the potential savings in traditional water sources. Additionally, it seeks to inform users about the status of traditional water sources and the inventory of sources available for reuse.

The application developed for this research, WaterWise, provides detailed information on water volumes from six sources: surface water, recharge, wastewater, rainwater, stormwater, and agricultural runoff. WaterWise integrates various models and databases, using hydrological studies and GIS models to quantify water volumes accurately. Developed as an open-source software on Google Earth Engine, WaterWise ensures cross-platform compatibility, making it user-friendly, widely accessible, and cost-effective.

This paper presents a comprehensive water inventory for the contiguous U.S., covering over 30,000 communities and categorizing water sources into above mentioned six sources. It also introduces the WaterWise application, an open-access, user-friendly tool designed to bridge the technological gap and promote the adoption of water reuse. The study includes an analysis of regional variations in the potential of different water reuse sources to meet public supply and irrigation needs, providing a multi-scale assessment of water availability for reuse across the country.

2 Methods

Below, the general definitions of the water sources are described, followed by the volume estimation methods, the description of the tool, architecture, data sources, user interface, and functionality. In addition, this section provides a guide on how the application was designed and assembled and how it can be used.

2.1 Water inventory

Figure 1

2.1.1 Data sources

Climate data, including precipitation, runoff, and recharge, were essential for calculating available water volumes. Additionally, geographic boundaries for cities, counties, and states in the contiguous U.S. were necessary for the technical component. Table 1 lists the datasets utilized in this research.

These datasets were chosen based on several factors, including their broad coverage, ease of access, and the nature of the information they provide. Census Bureau data provides a current and reliable source of up-to-date detailed information on political boundaries. Similarly, climate models such as the Coupled Model Intercomparison Project Phase 6 (CMIP6), were selected as the most recent generation of climate projections (Hausfather, 2019) and the fifth generation of European Centre for Medium-Range Weather Forecasts (ERA5) was selected as the reanalysis dataset, because it contains runoff data validated against a global network of river discharge observation stations (Harrigan et al., 2020). Additionally, each dataset was chosen due to its compatibility and availability within the Google Earth Engine database.

It is important to note that traditional water sources, such as surface runoff and recharge, are provided here primarily for reference and comparative purposes. They do not represent directly quantifiable volumes available for reuse. In contrast, the reuse sources (rainwater, stormwater, treated wastewater, and surface runoff from cultivated lands) represent estimations of water volumes that could potentially be captured or managed for local reuse applications. This distinction ensures that each community’s potential for reuse is assessed independently, while maintaining a baseline understanding of overall water availability.

2.1.2 Volume estimation

The basic unit of analysis is each community within the contiguous U.S., and the time scale is annual. We utilized GIS tools and models to compute the available volumes for each source. Below, we summarize the techniques employed for each source:

2.1.2.1 Surface runoff

A watershed draining to the point of maximum flow accumulation within the city was generated for each small community. Once the drainage areas for each community were established, runoff was integrated in space and time. The temporal integration consisted of aggregating all daily ERA5 (Earth Engine Data Catalog, 2025) model data to an annual scale, while the spatial integration involved extracting the mean value of the data within the analysis area, which in this case was each watershed. Finally, the available annual surface runoff volumes for each community were obtained. Annual averages were calculated using historical data from 1990 to 2020.

2.1.2.2 Recharge

As with surface runoff, watersheds associated with each community were used, except that the variable to integrate both temporally and spatially was recharge, derived from the Water Atlas (Tidwell and Jeffers, 2021). In the Water Atlas (Tidwell and Jeffers, 2021), the variable recharge refers to the process by which water infiltrates from the Earth’s surface into underground aquifers.

2.1.2.3 Rainwater

Normal precipitation values, which represent the average precipitation over a standard 30-year period, were calculated for this water source using data from CMIP6 climate model (Hausfather, 2019). In this case, only the precipitation falling on building rooftops was considered. The total rooftop area was estimated using the FEMA structures dataset (FEMA, 2022), and the corresponding rainwater volume was calculated for this area. Cintura and Arenas (2024) describe this specific reuse source in more detail. Annual averages were calculated using historical data from 1990 to 2020.

2.1.2.4 Stormwater

As with rainwater, the CMIP6 climate model and precipitation variable were used, but this time, the area considered included all developed zones, ranging from low, medium, to high intensity. To estimate monthly and annual stormwater volumes, we applied a simplified adaptation of the rational method using different coefficients based on the level of development. In this adaptation the formula for calculating the volumes is given in Equation 1:where V is the volume, is the runoff coefficient, Pis the precipitation depth and A is the drainage area. The runoff coefficients were selected based on standard values commonly used in hydrological studies for different levels of urban development (Mukhopadhyay and Singh, 2024). Specifically, the runoff coefficients used were 0.5 for low-density areas, 0.6 for medium-density areas, and 0.9 for high-density areas (Mukhopadhyay and Singh, 2024). The rational method formula is widely used in hydrology for estimating peak discharge from small catchment areas (USDA, 1986). Annual averages for each water source were calculated using historical data from 1990 to 2020.

2.1.2.5 Wastewater

This study utilizes the variable “treated wastewater,” as outlined in the article “Country-level and gridded estimates of wastewater production, collection, treatment, and reuse” (Jones et al., 2021). Treated wastewater refers to water that has undergone various treatment processes to remove contaminants and pathogens, making it suitable for reuse in non-potable applications. These processes may include physical, chemical, and biological methods to ensure the water meets the required quality standards for reuse (Reddy et al., 2023).

2.1.2.6 Agricultural runoff

As with surface runoff, this source considers the watershed associated with each community. For each watershed, the percentage of cultivated land cover was estimated using the National Land Cover Dataset—NLCD (U.S. Geological Survey, 2021), and the runoff variable (Earth Engine Data Catalog, 2025) was integrated temporally and spatially over the cultivated areas only.

To integrate the multiscale tool, once the volumes were estimated at the community level, the totals for each water source were aggregated at the county, state, and multiple Hydrologic Unit Code (HUC) levels. Annual averages were calculated using historical data from 1990 to 2020.

In summary, traditional sources (surface runoff, recharge, treated wastewater) are based on re-aggregations of validated existing datasets, whereas reuse sources (rainwater, stormwater) are derived from new calculations based on processed geospatial and precipitation data. Agricultural runoff is computed from existing surface runoff data over cultivated areas, ensuring consistency with validated datasets.

The water sources directly linked to precipitation and runoff variables were analyzed over the 1990–2020 period, and annual averages were calculated to provide representative long-term values. In contrast, for wastewater and recharge, the most recent available datasets were used, as wastewater volumes are strongly influenced by population growth and infrastructure development. Using the latest data ensures that these sources reflect current conditions.

2.1.3 Volume validation

For some sources where volumes could be validated, such as surface water, the validation was performed using observed data from USGS gages (USGS Water Data for the Nation, n.d.). This validation was carried out by climatic regions. Runoff data from the ERA5 dataset (ECMWF Reanalysis 5th Generation) (Hersbach et al., 2020) was assessed, and the results were analyzed using statistical indices, following guidelines based on various standards and references (Carlos Mendoza et al., 2021; Fernandez et al., 2005; Moriasi et al., 2007; Van Liew et al., 2003) to determine their acceptability. Figure 2A shows the surface water validation; the upper panel shows the watershed areas used for validation; on the lower panel is the chart where each point represents a drainage area, and three drainage areas were selected for each U.S. climatic region (runoff is expressed as equivalent depth across the watershed). With an R² coefficient of 0.83, the methodology is considered validated, yielding results that closely align with the observed data, which, according to Moriasi et al. (2007), is considered a ‘very good’ model performance evaluation for any R² value above 0.75.

Figure 2

Treated wastewater volumes were compared with public water supply (Luukkonen et al., 2024) to enable large-scale validation across the contiguous U.S. Figure 2B shows an R² value of 0.52, indicating a moderate correlation according to Moriasi et al. (2007). This relationship supports the reliability of treated wastewater data, as public water supply is strongly linked to population size and water usage patterns, which in turn influence wastewater generation. The alignment of these results is expected because higher water supply volumes generally lead to increased wastewater production, reflecting consistent trends in water consumption and discharge across communities. A perfect correlation is not expected due to factors such as climatic variability, infrastructure efficiency, water management regulations, and dataset development methodology. Nevertheless, this relationship serves as evidence supporting the accuracy of the treated wastewater dataset in the contiguous U.S. It should be noted that this moderate correlation represents a partial validation and should be considered when interpreting treated wastewater volumes, which are intended as high-level estimates rather than precise predictions.

For other water sources, including rainwater, stormwater, recharge and agricultural runoff, direct validation was not performed because these estimates rely on existing datasets that have already been validated in previous independent studies. Rainwater and stormwater calculations are based on precipitation data from established sources, while agricultural runoff uses the same surface runoff variable that was validated as described above. Consequently, these sources are considered reliable within the context of this study, and their estimates provide consistent and meaningful information for multi-scale assessment and comparison across communities.

2.2 WaterWise—interactive application

WaterWise is a solution to bridge the information gap. The application provides an easy-to-navigate interface for users to obtain the available water volumes for each source. It was built using the JavaScript code editor in the Google Earth engine.

Figure 3A displays the application’s interface.

Figure 3

The application has scalable architecture (analysis at the community, county, state and HUC levels) to provide easy handling for the user. The WaterWise application uses communities as the basis for the analysis, along with various aggregation levels. The architecture diagram is presented in Figure 3B. The target audience includes a wide range of users, from communities and counties to state and federal agencies. It is also of interest to the water sector for analyzing watershed-scale water management programs. The application architecture integrates data processed from Google Cloud Application Programming Interface (APIs) and ArcGIS Pro.

3 Results

This research produces a detailed water inventory for the contiguous United States, focusing on water volumes available for reuse. Accessible through the interactive WaterWise platform, this inventory provides essential data for assessing and managing water resources at various scales. It includes data for 48 states, 3,108 counties, and over 31,000 communities. The platform is reachable through the link: https://waterinventoryisu.users.earthengine.app/view/waterwise (accessed on March 5th, 2025). This open-access application requires no additional software beyond a web browser. The results can be exported as a file for further analysis.

The capabilities of the WaterWise application range from the individual selection of areas of interest for study to the multi-area selection for comparing available volumes. The application aggregates data results from the community level to various scales. While users can interact with WaterWise in real time, this manuscript highlights general analyses that provide insights of interest at the state and federal levels. Particularly, WaterWise enhances accessibility for small and underserved communities that often face limitations in technical capacity and data availability. Through its intuitive, web-based interface, the application allows users to visualize local water sources, assess potential for reuse, and compare results across spatial scales without requiring specialized software or training. This functionality helps local decision-makers identify feasible reuse strategies and supports more equitable participation in regional water planning.

As a result of the state-level water inventory, Figure 4 was generated to show the availability and distribution of water reuse sources by state. The sources included in this figure are stormwater, wastewater, and agricultural runoff. Rainwater is included in this study because, although it overlaps with stormwater in some contexts, it may be of particular interest to certain communities aiming to integrate this practice alongside others. For example, in some areas stormwater reuse may be implemented, while in others, rainwater harvesting may be more feasible or already in use. The analysis and discussion of these results are presented in the discussion section.

Figure 4

Furthermore, as part of the results, this research analyzed water reuse potential at the county scale for the contiguous U.S., identifying various sources that could meet public supply and irrigation needs. Figure 5 shows a map of the contiguous U.S. displaying public supply and irrigation datasets from the USGS (Alzraiee et al., 2024; U.S. Geological Survey, 2021, n.d), aggregated at the county scale for the year 2015. Additionally, it includes the NLCD data (U.S. Geological Survey, 2021), highlighting cultivated areas, with a base year of 2015. Figure 6 shows the distribution of reuse sources across the contiguous U.S., including stormwater, wastewater, and agricultural runoff.

Figure 5

Figure 6

Moreover, the results of this study provide insights into how well these water reuse sources can fulfill current water demand requirements, with public supply serving as the primary proxy for water demand in this context. The maps illustrate the potential of water reuse sources to meet public supply and irrigation are shown in Figure 7. The reference year for these analyses is 2015. Counties without irrigation are shown in white. A detailed analysis of these findings is presented in the discussion section.

Figure 7

4 Discussion

Water reuse presents a promising solution to the growing challenge of water scarcity in the United States. The findings from this study reveal that various sources of water reuse, including rainwater, stormwater, treated wastewater, and agricultural runoff, offer substantial potential for supplementing public supply and irrigation needs. However, the effectiveness of these sources varies across different regions of the country, with the eastern U.S. benefiting more significantly from water reuse opportunities than the western U.S., where water scarcity persists.

This discussion presents the findings in a structured manner, in line with the main objectives of the research: to create a comprehensive water inventory for the contiguous U.S., to develop the WaterWise application as a tool to bridge technological gaps, and to analyze regional variations in water reuse potential. This chapter is organized to first examine regional variations in water reuse potential, describing the distribution of water source availability in different areas. Next, the section on the potential to meet public supply and irrigation needs provides a structured overview of how water reuse could address the different water demands in the country. Finally, the section on challenges and opportunities in implementing water reuse identifies key factors that may influence the adoption of water reuse practices.

4.1 Regional variations in water reuse potential

The central and eastern U.S. emerge as the most favorable regions for utilizing water reuse sources, primarily due to their challenges in balancing water demand with available resources, despite having abundant precipitation and surface water. Figure 4 shows that states in the Midwest, like Minnesota (MN), Wisconsin (WI), Illinois (IL), and Ohio (OH), stand out for their high availability of agricultural runoff, which is consistent with the region’s cropland distribution shown in Figure 5. This area is characterized by extensive agricultural activity (USDA, n.d.). On the other hand, wastewater availability is moderate in several of these states but is lower compared to the West and Northeast. This pattern aligns with the land use dynamics in the region, where agricultural expansion predominates over urbanization, influencing water reuse potential. These dynamics include the growth of agricultural land, limited urbanization, and economic and political factors that shape both water availability and the distribution of urban and rural areas (Zhou and Lv, 2020).

In the northeastern states, such as New York (NY), Massachusetts (MA), and New Jersey (NJ), there is a notable presence of wastewater and stormwater. However, agricultural runoff has a smaller presence compared to other regions. In southern states like Texas (TX), Georgia (GA), and Florida (FL), there is considerable variability in water sources. Texas, for instance, has a large proportion of agricultural runoff, while states like Georgia and Florida show more prominent availability of stormwater and wastewater. The southern region appears to balance all three sources, though the proportions vary by state.

Rainwater harvesting and stormwater capture present significant potential in the central and eastern regions, particularly for non-potable applications such as irrigation and industrial use. The higher volume of rainfall in the eastern U.S. contribute to a more reliable and sustainable supply of these water reuse sources (NOAA, 2012; Smith et al., 2011). Furthermore, treated wastewater in densely populated areas of the eastern U.S. can further complement public supply systems, reducing the demand for freshwater withdrawals from rivers and aquifers. Agricultural regions in the east, which are beginning to explore alternative irrigation methods, could also benefit from implementing these practices.

In contrast, the western U.S. faces far greater challenges in implementing water reuse as a means to support public supply and irrigation. Figure 4 reveals significant trends in the western region, which includes states like California (CA), Nevada (NV), Arizona (AZ), Utah (UT), and Washington (WA), which shows a higher availability of stormwater and wastewater, especially in California and Arizona, where both resources have a high percentage. The availability of agricultural runoff is generally lower, with exceptions in states like Washington. These results align with the distribution of cropland areas shown in Figure 5.

This region’s arid and semi-arid climate results in limited precipitation, making rainwater and stormwater less viable as reliable water sources (Ahmed et al., 2023). In regions like CA, NV, and AZ, where water scarcity is a significant challenge, agricultural runoff and treated wastewater become the primary sources of reusable water (Silber-Coats et al., 2024; UN Environment programme, 2024). However, even though these sources are often insufficient to meet the high irrigation demands and public supply needs, particularly during prolonged droughts. Managed aquifer recharge techniques, which store treated wastewater or agricultural runoff in underground aquifers, are increasingly seen as a critical strategy to complement groundwater supplies in these regions (Ferencz et al., 2024). These aquifer recharge techniques can be fed with reused water, improving sustainability and enhancing the feasibility of using alternative water sources.

Regional differences in climate, land use, and infrastructure critically shape the feasibility and effectiveness of water reuse across the U.S. For instance, the humid climate and extensive agricultural land in the Midwest and Northeast support diverse water reuse sources, including agricultural runoff and stormwater, with infrastructure adapted to these conditions. Conversely, the arid climate and limited precipitation in the western states constrain rainwater and stormwater availability, placing greater reliance on treated wastewater and managed aquifer recharge systems. Additionally, variations in urbanization levels and infrastructure capacity further influence the implementation and success of reuse programs, underscoring the need for region-specific strategies that account for these multifaceted factors.

4.2 Potential to meet public supply and irrigation

As a result of the analysis of Figure 7A for public water supply, rainwater presents the greatest potential. This is particularly true in urbanized areas, where developed land plays a significant role, and the amount of precipitation that can be collected in systems for later use is notable. The eastern United States benefits the most from this source due to the spatial precipitation patterns, with this region experiencing the most months of high rainfall throughout the year. As expected, the potential is lower in the western part of the country; however, there are still population centers of significant size where large volumes of rainwater could be collected.

On the other hand, rainwater harvested from rooftops exhibits a geographic distribution similar to stormwater, with higher potential in the eastern United States. However, stormwater generally offers greater potential and larger available volumes, as it captures runoff from broader surfaces beyond rooftops. In contrast, rainwater harvesting is limited to rooftop areas, resulting in lower yields. In smaller communities, where infrastructure may be limited, both sources can nonetheless play an important role in supplementing non-potable water supplies and easing demand on municipal systems (Koh and Teh, 2022).

Finally, treated wastewater can be used for non-potable applications, such as toilet flushing, garden irrigation, and industrial processes, thus freeing up potable water for essential uses (Kesari et al., 2021). The potential for treated wastewater is closely aligned with the spatial distribution of public supply (as shown in Figure 5).

Irrigation, especially in agricultural regions (see Figure 7B), is crucial, as cultivated areas are mainly concentrated in the Midwest, with some regions in the West and South of the United States that could greatly benefit from water reuse. Agricultural runoff provides alternative water sources that could be used to supplement irrigation in water-scarce areas, especially during periods of water limitations (Ben-Asher and Berliner, 1994; Sabir et al., 2024). The map in Figure 4 illustrates that agricultural runoff is the most readily available water source in much of the Midwest and the northern West, making it a critical resource for these regions. This information is crucial because the agricultural industry is the largest consumer of water, yet it is essential for food production and overall human development (Oweis, 2018). In line with this, Shit et al. (2024) emphasize that sustainable water management strategies must prioritize the agricultural sector to ensure long-term water availability and food security.

In summary, in the eastern United States, where precipitation is more abundant, rainwater and agricultural runoff can be captured and stored to meet water scarcity needs. However, in the western United States, where irrigation demands are high, treated wastewater becomes a more critical resource, although its availability is still constrained by lower population densities and the need for additional infrastructure to transport and treat the water effectively.

4.3 Public perception

Public acceptance is crucial for the success of water reuse initiatives, particularly for potable uses such as drinking and cooking, where community perceptions play a significant role. Therefore, awareness campaigns including public demonstrations of treatment processes and outcomes must be implemented. Additionally, independent audits conducted by members of the general public, public health authorities, and local courts are essential to ensure transparency, build trust, and guarantee the safety and reliability of these systems. Although there is growing acceptance of recycled water for non-potable applications, concerns about direct potable reuse persist, particularly due to health risks associated with the potential presence of residual chemical contaminants, microbial pathogens, and failures in treatment or monitoring systems (Harris-Lovett et al., 2015; Kemp et al., 2012). Effective communication strategies that educate the public on the safety and benefits of water reuse can enhance acceptance and participation (Price et al., 2015). As communities adopt water reuse for less sensitive applications like landscape irrigation, they may gradually become more open to its use in other areas, creating a domino effect of acceptance (Lizmawan et al., 2023).

In addition to raising awareness, meaningful community engagement plays a key role in the success of water reuse programs, particularly for portable applications. Involving local stakeholders in the planning, monitoring, and communication processes fosters trust, enhances transparency, and increases public willingness to adopt reuse solutions. When communities feel heard and informed, they are more likely to support and sustain such initiatives over time.

Although water quality is a concern, public perception is also strongly influenced by water availability. Studies suggest that knowledge about water scarcity and the potential benefits of water reuse can significantly influence public willingness to adopt these practices (Portman et al., 2022). When communities recognize their water challenges and the role reuse can play in alleviating them, support for such initiatives increases (Nahar and Moran, 2022). Understanding local water availability helps communities assess current resources, identify reuse opportunities, and develop tailored strategies that address their specific water needs and environmental conditions.

Accurate data on water availability informs the design and implementation of water reuse systems. Structured approaches that include continuous feedback and stakeholder learning can optimize water reuse efforts (Ramaprasad and Syn, 2024). Likewise, knowing the local water supply situation is vital to managing water resources sustainably, especially in regions facing water scarcity (Reddy et al., 2023). The water reuse regulatory landscape is also influenced by water resource availability. The choice of standards and regulations should reflect local conditions, including water availability (Wilcox et al., 2016). Regulations must balance being flexible enough to consider local water conditions and strict enough to protect public health and the environment, ensuring an adequate framework for water reuse. While our study does not include primary research on public perception, the regional findings on reuse potential (Figure 7) inform public engagement strategies. Public perception of water reuse is being addressed in a separate, forthcoming study, as it is a complex topic that warrants its own dedicated analysis.

Public acceptance of water reuse, particularly for potable uses, heavily relies on effective communication about its safety and benefits. As communities gain awareness of water challenges and reuse opportunities, their willingness to support such initiatives increases. Beyond public perception, water reuse’s economic and environmental implications are crucial at the community level. By reducing reliance on traditional water sources, communities can delay the costs of developing new infrastructure, while also generating environmental benefits like improved groundwater recharge and reduced ecological degradation from over-extraction of freshwater resources (Duong and Saphores, 2015). To prevent groundwater overexploitation, regulations should be established based on estimates of groundwater recharge volumes at county or regional levels, ensuring sustainable extraction aligned with natural replenishment rates.

4.4 Challenges and opportunities in water reuse implementation

The findings from this study emphasize the need for region-specific strategies when implementing water reuse systems for public supply and irrigation. While the eastern U.S. enjoys relatively favorable conditions for water reuse, the western U.S. faces significant challenges that will require more innovative approaches. These challenges include not only the need for advanced water treatment technologies but also the development of infrastructure to store, transport, and distribute reused water.

In the U.S., states like California, Arizona, Texas, and Florida have developed comprehensive water reuse programs to address challenges from drought, population growth, and resource limitations (EPA, 2018; Water Research Foundation, 2021; Water Reuse Association, 2018). California leads with extensive regulatory frameworks for agricultural, industrial, and even direct potable reuse systems, like the Orange County Water District’s Groundwater Replenishment System (Water Research Foundation, 2021). Arizona focuses on aquifer recharge and non-potable uses, leveraging its Aquifer Protection Permit program (Water Reuse Association, 2018), while Texas uses both indirect and direct potable reuse to enhance its water supply, notably in drought-prone areas like Wichita Falls (EPA, 2018). Florida, with one of the largest reuse programs, uses reclaimed water to protect freshwater resources and support high-demand areas (Water Research Foundation, 2021). These states provide adaptive models for sustainable water management across varying climates and population pressures.

Major barriers to implementing water reuse systems, especially in the water-scarce western U.S., include technological, regulatory, and economic challenges. Advanced treatment technologies are essential to ensure safety and cost-effectiveness. Regulatory frameworks vary widely, making it difficult to scale solutions consistently. High capital and operational costs for treatment and distribution infrastructure also limit adoption. Addressing these issues requires integrated approaches combining innovation, policy support, and stakeholder engagement. Lessons from leading states like California, Texas, and Florida; such as regulatory clarity, community involvement, and diverse reuse strategies, can guide other regions in developing adaptable and sustainable water reuse programs.

Furthermore, public acceptance of reused water remains a critical issue, particularly for potable uses. Research indicates that public perceptions are often influenced by the perceived health risks associated with treated wastewater, which can deter communities from supporting reuse initiatives (Akpan et al., 2020; Smith et al., 2018; Wester et al., 2016). Effective communication strategies that highlight the safety and benefits of water reuse are essential to overcoming these barriers (Liu et al., 2021; Neri et al., 2024; Tortajada and Nambiar, 2019). Moreover, involving community stakeholders in the planning and decision-making processes can enhance transparency and trust, thereby improving public acceptance (Flint and Koci, 2021; Frijns et al., 2016). This research provides essential insights for building public trust and effectively communicating the benefits of water reuse. Through the analyses presented in this study and the interactive multi-scale application, we offer valuable tools to help overcome acceptance barriers, fostering widespread adoption of sustainable water reuse practices across the United States.

5 Limitations and considerations

While this study examines various aspects of water reuse in communities on an annual scale, it focuses exclusively on quantifying available water volumes and does not account for factors crucial to the detailed design or feasibility of capture and treatment systems. One such factor is the analysis of seasonal or daily patterns in variables like precipitation, which could significantly impact system design by affecting how the systems are sized and optimized to handle varying water availability. This study uses normal precipitation values, representing the average precipitation over a standard 30-year period (1990–2020), which smooth out short-term variability but may not capture finer-scale fluctuations critical for system optimization. The WaterWise application is intended primarily to analyze alternative reuse practices. A detailed analysis incorporating these factors is recommended to optimize the design and implementation of reuse systems.

Although the geospatial and reanalysis datasets used in this study differ in spatial and temporal resolution, the analytical framework was designed to ensure consistency and scalability across all spatial levels. Water volume estimates are based on existing public datasets, each of which has its own documented uncertainty that has been thoroughly studied and validated in previous independent research; assessing these uncertainties individually is beyond the scope of this study. Processing and validation steps, described in the Methods section, were applied to ensure agreement among the multi-scale assessments. Some regional variations in data resolution or quality may persist; however, these do not significantly affect the overall trends or comparative results presented here. This approach provides high-level, reliable estimates suitable for screening and comparison across communities, while acknowledging inherent variability when integrating multiple sources.

Additionally, estimates of available water based on watersheds, such as surface runoff, may be affected if this source is imported from another watershed. Water transfers occur on a large scale to support municipal, industrial, and agricultural needs. For example, the Denver Water system moves water up to 250 miles from reservoirs west of the Continental Divide to supply the Denver area (Medalie et al., 2025). Similarly, the New York City water supply system transports over 1 billion gallons daily across 125 miles to serve nearly 10 million residents (Medalie et al., 2025). In such cases, it is advisable for users to manually select the watershed or community from which the water is imported for volume analysis. Addressing these factors is crucial for comprehensively evaluating water management practices.

Stormwater volumes in this study were estimated using a simplified adaptation of the Rational Method, in which annual precipitation over developed areas is multiplied by runoff coefficients corresponding to low, medium, and high-density development. This approach provides high-level, community-scale estimates suitable for screening and comparison rather than precise hydraulic modeling. We acknowledge that this simplification does not account for infiltration dynamics, seasonal evapotranspiration, or antecedent moisture conditions, which could affect the actual runoff volume. Users should interpret these values as indicative of relative potential rather than exact measurements, and the associated uncertainty is inherent to this high-level estimation.

In addition, a limitation of this study is the absence of a detailed geo-hydrological analysis in the assessment of groundwater recharge. Accurate estimation of recharge potential requires an in-depth understanding of local geological formations and hydrological processes, which were not incorporated in the current evaluation. Addressing this gap in future research will enhance the precision and applicability of groundwater recharge assessments within water reuse planning.

While agricultural runoff volumes are estimated in this study, it is important to note that these flows are part of the downstream hydrological budget and are subject to water rights, environmental flow requirements, and water quality regulations. The purpose of this research is to provide a high-level inventory of potential water volumes for planning and screening purposes, not to assess the legal, ecological, or economic feasibility of capturing or reusing these flows. Detailed site-specific analyses would be required to evaluate the practical implementation of reuse strategies for agricultural runoff.

Human health must be a fundamental concern when reusing treated water for irrigation. If water quality is not rigorously monitored, there is a risk of infectious diseases, heavy metal contamination, and exposure to organic pollutants, which can pose serious threats to both agricultural workers and consumers (Ramm and Smol, 2023). Therefore, it is essential to establish strict quality controls and treatment standards to ensure the safety of reused water in agriculture. At the same time, it is necessary to promote innovation in nature-based solutions to reduce water consumption at the level of individual farming plots and domestic use. Strategies such as rainwater harvesting, soil moisture conservation, and agroforestry can decrease reliance on irrigation and promote more sustainable water use in agriculture and rural households.

6 Conclusion

While the potential of water reuse to address water scarcity is significant, its effectiveness depends heavily on regional conditions. Tailored approaches that consider local climate, water availability, and infrastructure capacity are essential to maximize the benefits of water reuse for public supply and irrigation across communities in the contiguous U.S.

As water scarcity continues to increase, particularly in western states, water reuse will become an even more critical component of integrated water management strategies. This study highlights the potential of water reuse to relieve stress on traditional water sources, while emphasizing the need for strategies that account for regional differences in availability and demand.

The eastern U.S. has a clear advantage for implementing water reuse due to its favorable climate, positioning it to adopt innovative practices more readily. In contrast, the western U.S. must invest in advanced technologies and infrastructure to fully exploit limited water reuse sources, particularly treated wastewater and agricultural runoff. Water reuse strategies must therefore be tailored to each region, reflecting variations in climate, demographics, and economic conditions.

While water reuse offers considerable potential to enhance public supply and irrigation, its success is highly dependent on local conditions. Region-specific approaches that integrate technological innovation, public education, and infrastructure development are necessary, especially in water-scarce western areas. In this context, the WaterWise application provides critical data and insights to support informed decision-making and the adoption of sustainable water practices.

Furthermore, county-level innovations in nature-based solutions to reduce water use in agriculture and households should be prioritized within integrated reuse strategies. Practices such as rainwater harvesting and soil moisture conservation can significantly improve local water sustainability. At the same time, rigorous attention to water irrigation is crucial to mitigating risks from pathogens, heavy metals, and organic contaminants. Ensuring strict monitoring and treatment standards is essential to protect public health while fully realizing the benefits of water reuse.

References

• 1

  Ahmed S. Jesson M. Sharifi S. (2023). Selection frameworks for potential rainwater harvesting sites in arid and semi-arid regions: a systematic literature review. Water15:2782. doi: 10.3390/W15152782

  • CrossRef
  • Google Scholar

• 2

  Akpan V. E. Omole D. O. Bassey D. E. (2020). Assessing the public perceptions of treated wastewater reuse: opportunities and implications for urban communities in developing countries. Heliyon6:e05246. doi: 10.1016/J.HELIYON.2020.E05246,

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 3

  Alzraiee A. Niswonger R. Luukkonen C. Larsen J. Martin D. Herbert D. et al . (2024). Next generation public supply water withdrawal estimation for the conterminous United States using machine learning and operational frameworks. Water Resour. Res.60. doi: 10.1029/2023WR036632

  • CrossRef
  • Google Scholar

• 4

  Angelakis A. N. Asano T. Bahri A. Jimenez B. E. Tchobanoglous G. (2018). Water reuse: from ancient to modern times and the future. Front. Environ. Sci.6:366552. doi: 10.3389/FENVS.2018.00026

  • CrossRef
  • Google Scholar

• 5

  Ben-Asher J. Berliner P. R. (1994). “Runoff irrigation” in Management of water use in agriculture, 126–154. doi: 10.1007/978-3-642-78562-7_6

  • CrossRef
  • Google Scholar

• 6

  Biswas A. Sarkar S. Das S. Dutta S. Roy Choudhury M. Giri A. et al . (2025). Water scarcity: a global hindrance to sustainable development and agricultural production – a critical review of the impacts and adaptation strategies. Cambridge Prisms: Water3:e4. doi: 10.1017/WAT.2024.16

  • CrossRef
  • Google Scholar

• 7

  Carlos Mendoza J. A. Chavez Alcazar T. A. Zuñiga Medina S. A. (2021). Calibration and uncertainty analysis for modelling runoff in the Tambo River basin, Peru, using sequential uncertainty fitting Ver-2 (SUFI-2) algorithm. Air Soil Water Res.14:117862212098870. doi: 10.1177/1178622120988707

  • CrossRef
  • Google Scholar

• 8

  Census Bureau (2022a) Census designated places. Available online at: https://www.census.gov/programs-surveys/bas/information/cdp.html (Accessed May 31, 2025)

  • Google Scholar

• 9

  Census Bureau (2022b) TIGER/line shapefiles. Available online at: https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.html (Accessed May 31, 2025)

  • Google Scholar

• 10

  Cintura I. Arenas A. (2024). Multi-scale assessment of rainwater harvesting availability across the continental U.S. J. Environ. Manag.366:121776. doi: 10.1016/J.JENVMAN.2024.121776,

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 11

  Duong K. Saphores J. D. M. (2015). Obstacles to wastewater reuse: an overview. Wiley Interdiscip. Rev. Water2, 199–214. doi: 10.1002/WAT2.1074

  • CrossRef
  • Google Scholar

• 12

  Earth Engine Data Catalog . (2025). ERA5-Land. Available online at: https://developers.google.com/earth-engine/datasets/catalog/ECMWF_ERA5_LAND_MONTHLY_AGGR (Accessed May 31, 2025)

  • Google Scholar

• 13

  EPA (2018) Mainstreaming potable water reuse in the United States: Strategies for Leveling the playing field. United States: Meridian Institute and Paradigm Environmental.

  • Google Scholar

• 14

  EPA . (2024). Onsite non-potable water reuse research | US EPA. Available online at: https://www.epa.gov/water-research/onsite-non-potable-water-reuse-research (Accessed May 31, 2025)

  • Google Scholar

• 15

  FEMA (2022) USA structures | FEMA geospatial resource Center. Available online at: https://gis-fema.hub.arcgis.com/pages/usa-structures (Accessed May 31, 2025)

  • Google Scholar

• 16

  Ferencz S. B. Mangel A. Day-Lewis F. (2024). Managed aquifer recharge as a strategy to redistribute excess surface flow to baseflow in snowmelt hydrologic regimes. Front. Water6:1375523. doi: 10.3389/FRWA.2024.1375523

  • CrossRef
  • Google Scholar

• 17

  Fernandez G. P. Chescheir G. M. Skaggs R. W. Amatya D. M. (2005). Development and testing of watershed-scale models for poorly drained soils. Trans. ASAE48, 639–652. doi: 10.13031/2013.18323

  • CrossRef
  • Google Scholar

• 18

  Flint C. G. Koci K. R. (2021). Local resident perceptions of water reuse in northern Utah. Water Environ. Res.93, 123–135. doi: 10.1002/WER.1367,

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 19

  Frijns J. Smith H. M. Brouwer S. Garnett K. Elelman R. Jeffrey P. (2016). How governance regimes shape the implementation of water reuse schemes. Water8:605. doi: 10.3390/W8120605

  • CrossRef
  • Google Scholar

• 20

  Harrigan S. Zsoter E. Alfieri L. Prudhomme C. Salamon P. Wetterhall F. et al . (2020). GloFAS-ERA5 operational global river discharge reanalysis 1979-present. Earth Syst. Sci. Data12, 2043–2060. doi: 10.5194/ESSD-12-2043-2020

  • CrossRef
  • Google Scholar

• 21

  Harris-Lovett S. R. Binz C. Sedlak D. L. Kiparsky M. Truffer B. (2015). Beyond user acceptance: a legitimacy framework for potable water reuse in California. Environ. Sci. Technol.49, 7552–7561. doi: 10.1021/acs.est.5b00504

  • CrossRef
  • Google Scholar

• 22

  Hausfather Zeke (2019) CMIP6: the next generation of climate models explained - carbon brief. Available online at: https://www.carbonbrief.org/cmip6-the-next-generation-of-climate-models-explained/ (Accessed May 31, 2025)

  • Google Scholar

• 23

  Hersbach H. Bell B. Berrisford P. Hirahara S. Horányi A. Muñoz-Sabater J. et al . (2020). The ERA5 global reanalysis. Q. J. R. Meteorol. Soc.146, 1999–2049. doi: 10.1002/QJ.3803

  • CrossRef
  • Google Scholar

• 24

  Jones E. R. Van Vliet M. T. H. Qadir M. Bierkens M. F. P. (2021). Country-level and gridded estimates of wastewater production, collection, treatment and reuse. Earth Syst. Sci. Data13, 237–254. doi: 10.5194/ESSD-13-237-2021

  • CrossRef
  • Google Scholar

• 25

  Kemp B. Randle M. Hurlimann A. Dolnicar S. (2012). Community acceptance of recycled water: can we inoculate the public against scare campaigns?J. Public Aff.12, 337–346. doi: 10.1002/PA.1429

  • CrossRef
  • Google Scholar

• 26

  Kesari K. K. Soni R. Jamal Q. M. S. Tripathi P. Lal J. A. Jha N. K. et al . (2021). Wastewater treatment and reuse: a review of its applications and health implications. Water Air Soil Pollut.232, 1–28. doi: 10.1007/S11270-021-05154-8/FIGURES/5

  • CrossRef
  • Google Scholar

• 27

  Koh H. L. Teh S. Y. (2022). “Urban stormwater Management for Future Cities: Sustainable and innovative approaches” in Clean water and sanitation, 644–658.

  • Google Scholar

• 28

  Liu Q. Yang L. Yang M. (2021). Digitalisation for water sustainability: barriers to implementing circular economy in smart water management. Sustainability13:11868. doi: 10.3390/SU132111868

  • CrossRef
  • Google Scholar

• 29

  Lizmawan F. Putri D. W. Maryati S. (2023). Public acceptance of utilization of water reuse in community-based sanitation infrastructure (case study: Bandung City). J. Sains Dan Kesehat.5, 829–836. doi: 10.25026/JSK.V5I5.1869

  • CrossRef
  • Google Scholar

• 30

  Luukkonen C. L. Alzraiee A. H. Larsen J. D. Martin D. J. Herbert D. M. Buchwald C. A. et al . 2024 Public supply water use reanalysis. Public supply water use reanalysis for the 2000-2020 period by HUC12, month, and year for the conterminous United States. U.S. Geological Survey data release. Available online at: https://www.sciencebase.gov/catalog/item/65f86970d34e97daac9ff4c8

  • Google Scholar

• 31

  Medalie L. Galanter A. E. Martinez A. J. Archer A. A. Luukkonen C. L. Harris M. A. et al . (2025). Water use across the conterminous United States, water years 2010–20. Prof. Pap. doi: 10.3133/PP1894D

  • CrossRef
  • Google Scholar

• 32

  Moriasi D. N. Arnold J. G. Liew M. W. Van, BingnerR. L.HarmelR. D.VeithT. L. (2007). Model evaluation guidelines for systematic quantification of accuracy in watershed simulations. Trans. ASABE, 50, 885–900. Doi:doi: 10.13031/2013.23153

  • CrossRef
  • Google Scholar

• 33

  Mukhopadhyay B. Singh V. P. (2024). “The rational method” in Applied hydrology, 442–453.

  • Google Scholar

• 34

  Nahar S. Moran S. (2022). “Local communities in water and sanitation: practices and challenges” in Clean water and sanitation, 390–401.

  • Google Scholar

• 35

  Neri A. Rizzuni A. Garrone P. Cagno E. (2024). Barriers and drivers to the development of an effective water reuse chain: insights from an Italian water utility. Clean Techn. Environ. Policy27, 1617–1637. doi: 10.1007/S10098-024-02899-8/TABLES/7

  • CrossRef
  • Google Scholar

• 36

  NOAA (2012) Precipitation-frequency atlas of the United States

  • Google Scholar

• 37

  Org J. Drewes E. Horstmeyer N. Drewes J. E. Horstmeyer N. (2015). “Recent developments in potable water reuse” in The handbook of environmental chemistry. eds. BarcelóD.KostianoyA. G., 269–290.

  • Google Scholar

• 38

  Oweis T. (2018). Water management for sustainable agriculture. In Water management for sustainable agriculture (T Oweis). London: Burleigh Dodds Science Publishing

  • Google Scholar

• 39

  Portman M. E. Vdov O. Schuetze M. Gilboa Y. Friedler E. (2022). Public perceptions and perspectives on alternative sources of water for reuse generated at the household level. Water Reuse12, 157–174. doi: 10.2166/WRD.2022.002,

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 40

  Price J. Fielding K. S. Gardner J. Leviston Z. Green M. (2015). Developing effective messages about potable recycled water: the importance of message structure and content. Water Resour. Res.51, 2174–2187. doi: 10.1002/2014WR016514

  • CrossRef
  • Google Scholar

• 41

  Ramaprasad A. Syn T. (2024). A framework for developing a national research strategy for water reuse. Recycling9:24:24. doi: 10.3390/RECYCLING9020024

  • CrossRef
  • Google Scholar

• 42

  Ramm K. Smol M. (2023). Water reuse—analysis of the possibility of using reclaimed water depending on the quality class in the European countries. Sustainability15:12781. doi: 10.3390/SU151712781

  • CrossRef
  • Google Scholar

• 43

  Reddy K. R. Kandou V. Havrelock R. El-Khattabi A. R. Cordova T. Wilson M. D. et al . (2023). Reuse of treated wastewater: drivers, regulations, technologies, case studies, and greater Chicago area experiences. Sustainability15:7495. doi: 10.3390/SU15097495

  • CrossRef
  • Google Scholar

• 44

  Sabir R. M. Sarwar A. Shoaib M. Saleem A. Alhousain M. H. Wajid S. A. et al . (2024). “Managing water resources for sustainable agricultural production” in Transforming agricultural management for a sustainable future, 47–74.

  • Google Scholar

• 45

  Shit P. K. Adhikary P. P. Bera B. Rajput V. D. (2024). Resilient and sustainable water management in agriculture. Environ. Sci. Pollut. Res.31, 54020–54025. doi: 10.1007/S11356-024-34003-4,

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 46

  Shoushtarian F. Negahban-Azar M. (2020). Worldwide regulations and guidelines for agricultural water reuse: a critical review. Water12:971. doi: 10.3390/W12040971

  • CrossRef
  • Google Scholar

• 47

  Silber-Coats N. Elias E. Steele C. Fernald K. Gagliardi M. Hrozencik A. et al . (2024). The water adaptation techniques atlas: a new geospatial library of solutions to water scarcity in the U.S. southwest. PLoS Water3:e0000246. doi: 10.1371/JOURNAL.PWAT.0000246

  • CrossRef
  • Google Scholar

• 48

  Singha B. Eljamal O. (2022). Evaluating the social and psychological factors about the public acceptance of treated wastewater reuse: a review. Proc. Int. Exchange Innov. Conf. Eng. Sci.8, 234–238. doi: 10.5109/5909097

  • CrossRef
  • Google Scholar

• 49

  Smith H. M. Brouwer S. Jeffrey P. Frijns J. (2018). Public responses to water reuse – understanding the evidence. J. Environ. Manag.207, 43–50. doi: 10.1016/J.JENVMAN.2017.11.021,

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 50

  Smith J. A. Villarini G. Baeck M. L. (2011). Mixture distributions and the hydroclimatology of extreme rainfall and flooding in the eastern United States. J. Hydrometeorol.12, 294–309. doi: 10.1175/2010JHM1242.1

  • CrossRef
  • Google Scholar

• 51

  Stets E. G. Archer A. A. Degnan J. R. Erickson M. L. Gorski G. A. Medalie L. et al . 2025. U.S. Geological Survey integrated water availability assessment—2010–20. Professional paper.

  • Google Scholar

• 52

  Tidwell V. Jeffers R. (2021). Water atlas features database. Available online at: https://www.osti.gov/biblio/1756186 (Accessed December 3, 2025).

  • Google Scholar

• 53

  Tortajada C. Nambiar S. (2019). Communications on technological innovations: potable water reuse. Water11:251. doi: 10.3390/W11020251

  • CrossRef
  • Google Scholar

• 54

  U.S. Geological Survey (2021). NLCDhttps://www.mrlc.gov/ (Accessed May 31, 2025)

  • Google Scholar

• 55

  U.S. Geological Survey (2023). National hydrography dataset. Available online at: https://www.usgs.gov/national-hydrography/national-hydrography-dataset (Accessed May 31, 2025)

  • Google Scholar

• 56

  U.S. Geological Survey . (n.d.). Water use in the United States. Available online at: https://www.usgs.gov/mission-areas/water-resources/science/water-use-united-states (Accessed November 5, 2024)

  • Google Scholar

• 57

  UN Environment Programme (2024). As the climate dries, American west faces problematic future. Available online at: https://www.unep.org/news-and-stories/story/climate-dries-american-west-faces-problematic-future-experts-warn (Accessed May 31, 2025)

  • Google Scholar

• 58

  United Nations Educational Scientific and Cultural Organization . (2021). The United Nations world water development report 2021: Valuing water. Water politics. Available online at: https://unesdoc.unesco.org/ark:/48223/pf0000375724 (Accessed May 31, 2025)

  • Google Scholar

• 59

  USDA . (1986). Urban hydrology for small watersheds

  • Google Scholar

• 60

  USDA . (n.d.). Agriculture in the Midwest | USDA climate hubs. Available online at: https://www.climatehubs.usda.gov/hubs/midwest/topic/agriculture-midwest (Accessed November 6, 2024)

  • Google Scholar

• 61

  USGCRP . (2023). Fifth National Climate Assessment. 1–470

  • Google Scholar

• 62

  USGS Water Data for the Nation . (n.d.). Available online at: https://waterdata.usgs.gov/nwis (Accessed July 25, 2025)

  • Google Scholar

• 63

  Van Liew M. W. Arnold J. G. Garbrecht J. D. (2003). Hydrologic simulation on agricultural watersheds: choosing between two models. Trans. ASABE46, 1539–1551. doi: 10.13031/2013.15643

  • CrossRef
  • Google Scholar

• 64

  Water Reuse Association (2018). New report provides recommendations for the regulation of direct potable reuse In Arizona. Available online at: https://watereuse.org/report-available-that-provides-recommendations-for-the-regulation-of-direct-potable-reuse-in-arizona/

  • Google Scholar

• 65

  Water Research Foundation (2021) Reuse. Available online at: https://www.waterrf.org/research/topics/reuse (Accessed May 31, 2025)

  • Google Scholar

• 66

  Wester J. Timpano K. R. Çek D. Broad K. (2016). The psychology of recycled water: factors predicting disgust and willingness to use. Water Resour. Res.52, 3212–3226. doi: 10.1002/2015WR018340

  • CrossRef
  • Google Scholar

• 67

  Wilcox J. Nasiri F. Bell S. Rahaman M. S. (2016). Urban water reuse: a triple bottom line assessment framework and review. Sustain. Cities Soc.27, 448–456. doi: 10.1016/J.SCS.2016.06.021

  • CrossRef
  • Google Scholar

• 68

  Zhou B. B. Lv L. (2020). Understanding the dynamics of farmland loss in a rapidly urbanizing region: a problem-driven, diagnostic approach to landscape sustainability. Landsc. Ecol.35, 2471–2486. doi: 10.1007/S10980-020-01074-W/FIGURES/7

  • CrossRef
  • Google Scholar