Drinking water service area boundaries are critical for state policy and operations - and some state agencies are working with local water systems to develop this foundational data set.

States across the country recognize the value of water service area boundaries – from water supply and demand projections to regionalization studies and emergency response. State and local partnerships can help ensure that this data is accurate, accessible, and useful to a range of applications.

In May, EPIC, the Internet of Water Coalition, and SimpleLab released a provisional national map of drinking water service area boundaries to support the design and implementation of environmental justice, water and climate programs at the federal, state, and community levels. Over the summer, EPIC is publishing a series of blogs that explore why water service area boundaries are particularly important to individuals, communities, water system managers, and state and federal agencies. This blog post explores how four states – New Mexico, North Carolina, Utah, and California – approached the development of water service area boundaries, and how other states can institute policies and fund the development of their own service area boundary datasets.


There are nearly 50,000 community water systems in the United States that serve 90 percent of the population. And despite the importance of water to health, safety, economic mobility, and overall well being, we do not have a comprehensive, accurate map of who those systems serve. State agencies - who are primarily responsible for drinking water oversight - need service area boundaries to identify with precision which communities lack access to safe, reliable, and affordable drinking water, and to adequately understand and plan for drought or natural disasters. They also can play a critical role in ensuring that water service area boundaries are made publicly available so that every person can easily discover who is responsible for the water they drink at home, at work, at school, or at play. 

Fourteen states currently have publicly available service area boundary data that they have collected for a plethora of uses. The agencies involved, the funding sources leveraged, and the policies used for both gathering and using service area boundary data vary from state to state. They present a spectrum of options that could be adopted and adapted by other states hoping to produce and use service area boundary data.


Fourteen states have publicly available service area boundary data. Other states may have a smaller subset of service area boundary data available to the public, full datasets that are not publicly available, or lack service area boundaries.


Over the summer, EPIC interviewed leaders from four states - New Mexico, North Carolina, Utah, California - to understand how states developed this critical dataset: Why were service area boundaries collected and shared, what agencies were involved in initial development and ongoing maintenance, how was the work funded, what policies were used to collect data, and how did each state work with local communities?

Here’s what we learned:

There are many uses for accurate and accessible service boundary data.

States named how helpful this data set is for the following applications: 

  • Projecting populations to estimate future water supply and demand (UT, NC); 

  • Estimating domestic well use in areas not served by community water systems (NM);

  • Evaluating alternative water supply options (NM, CA); 

  • Assessing climate change variability, including wildfire impacts on water supply (NM, CA); 

  • Connecting water quality information to income and demographic data to inform grant eligibility and prioritization of State Revolving Fund allocations (CA); 

  • Inter-agency collaboration (UT, NC); 

  • Facilitating academic research (UT, CA, NC); and 

  • Public interest (UT). 

States stressed that identifying those applications and communicating the value of boundary data is critical to secure approval from policy-makers and support from local systems. Many state water agencies and water systems alike are already overworked and understaffed, so “aligning use with interest” is key. 

Developing the data is not particularly costly, but it can take time.

New Mexico’s Office of the State Engineer developed their service area boundaries using a Water-Use Data and Research grant from the US Geological Survey. This grant had criteria that all states had to meet for their 5-year report, which coincided with the water use planning assessments that New Mexico publishes every five years. Contracting a private consulting firm named HydroAnalytics, it took roughly $90,000 and one year to collect, digitize, and standardize the service area boundary data for 600 of New Mexico’s 632 community water systems. The data, which was collected using direct outreach to systems and through the comparison of water rights maps to google maps, were published as a work in progress that includes information about relative data quality of each boundary.

EPIC estimates the cost of initial service area boundary development between $150 and $300 per water system. For a state with few community water systems, like Wyoming, this would be $50 to $100 thousand, while a larger state like Florida would require $250 to $500 thousand. Long term maintenance cost is more difficult to estimate and depends on the frequency of boundary updates and the ability to integrate updates into other programs, such as site visits for sanitary surveys. Regardless of the method, ongoing maintenance is an essential part of ensuring the service area boundaries remain accurate and useful over time. 

States looking for external funding for service area map development may explore the Water-Use Data and Research grant from USGS or EPA’s Exchange Network Grant Program. Some states we interviewed used existing state funding to support this work, while others secured federal grant funding. Universities who assisted in service area map development complemented state efforts with their own external funding and technical resources. With increased federal funding for water infrastructure coming down the pipeline, we expect more grant funding to be available for more states to develop these data.

However, funding data development is only half the battle for states that do not have the technical expertise or human resources to actually develop the data. While some states relied on the agency’s internal GIS team to do the work, others contracted with external consultants to develop water service area boundaries; still others worked with universities.

There is value in publishing provisional data that can improve over time.

Of course, any approach requires close partnership with local communities and individual water systems - which can take time and persistence. States advised that it is important to have realistic expectations about funding and time to have conversations with stakeholders. Some local water systems were very responsive to requests to develop this data, whereas others required multiple modes of outreach. Given that this effort takes time, states recognized the value in publishing data as it is available and improving the accuracy over time (as opposed to waiting to publish until the data was 95% accurate), so long as the data included disclaimers about the data quality and provision of metadata. One state named that there will always be the last 10-15% of systems that do not respond, but even an incomplete data set is tremendously helpful. 

Planning and partnerships help the process.

States named a range of planning activities that could help efforts to develop water service area boundaries:

  • Data development will be more successful and efficient if the project lead specifies the requested map format - for example, if a water system sends a photo of a physical map that was originally created using GIS software, it takes more time to turn that photo back into a digital GIS file and likely introduces errors and reduces the accuracy of the final product. Requesting GIS files whenever available reduces work for both the water system and state agency and prevents the introduction of mapping errors. 

  • Projects will garner more support if their value can be concretely demonstrated - the creation of a few example service area maps can help people conceptualize the project and secure buy-in from higher ups within state agencies and from local stakeholders. An abstract description of the uses of service area boundaries without anything to show will fail to gain support.

  • If a state agency works with a contractor, specify exactly the precision required of the maps to make them useful and what other data fields need to be included with the data. A precise boundary without the system’s Public Water System Identifier cannot be connected to other system data, such as water quality violations, and is not very useful to the state. We were surprised at how often such vital information was left out. 

  • Lastly, they encourage identifying how you will use the data. Demonstrating your incentive for the data will encourage better data quality because state stakeholders understand its importance and use. Water systems themselves are always balancing their scarce time between countless tasks, so one extra request from the state needs to be well justified.

  • States also talked about the importance of partnerships - especially with other government agencies. For example, one state representative noted that cross-agency collaboration can be difficult but that it opens doors to better communication with water systems, connections to other data sources, and perhaps different funding sources as well.

Tribal Water Systems

  • Tribal boundaries overlap with state boundaries and what is published by the state regarding tribal water systems varies from state to state with respect to data availability, accuracy, and long standing relationships.

  • Tribal water systems are not regulated by US states, though parts of some reservations may be served by non-tribal water systems.

  • Accessible service area boundary data may still be useful for individual tribal water systems and entire tribal governments for many of the same reasons they are useful to US states, such as water supply planning, emergency notifications, and regionalization studies.

  • EPIC is working to better understand these partnerships, how often water access and quality for tribes is well captured by the existing data, and where additional work is needed to form an accurate picture. We will publish our findings in a blog in the fall of 2022. 

Regulation can be helpful, but it is not necessary.

Many states were able to develop this data set without any regulatory requirements, although some noted that requirements would be useful. For example, after the 2007-08 drought, North Carolina adopted legislation requiring water systems to provide water use information to the Department of Environmental Quality; these reporting requirements include the provision of service area boundary maps. In Utah, the Division of Water Resources is the primary agency in charge of service area boundaries, but its sister agency with regulatory authority, the Division of Water Rights, physically visits water systems more frequently. During these site visits, DWRi staff request that water system personnel either verify their boundary data or provide updates that are then digitized by DWR staff. In New Mexico and California, there are no regulations in place requiring the submission of service area boundary maps to the state, but more than 90% of systems have voluntarily shared this information in both states when asked by the state.

States can successfully address any security concerns with sharing this data.

Though some water systems had security concerns about sharing their service area boundaries, state officials were able to assuage these concerns by clarifying that they did not need any infrastructure information, such as water lines or intakes. Public service area boundaries do not identify infrastructure location and are not associated with security concerns.

For more about each state’s journey to create this data, please see the state summaries below.

  • New Mexico’s Office of the State Engineer developed their service area boundaries using a Water-Use Data and Research grant from the US Geological Survey in 2019. This grant had criteria that all states had to meet for their 5-year report, which coincided with the water use planning assessments that New Mexico publishes every five years. Using a private consulting firm named HydroAnalytics, it took roughly $90,000 and one year to collect, digitize, and standardize the service area boundary data for 600 of New Mexico’s 625 community water systems. That’s an average of $150 per system. This data, which was collected using direct outreach to systems and through the comparison of water rights maps to google maps, was published as a work in progress and includes information about the relative data quality of each boundary. The service area boundaries have been used for a myriad of purposes including estimating domestic well use, assessing which water systems could benefit from a desalination plant, and the Climate Change Vulnerability Assessment to assess erosion risk, post-fire debris flow, resilience to climate change, and systems only relying on surface water amongst others. They will soon be used for the water use planning assessments that motivated their development in the first place.

  • Utah’s Division of Water Resources published their service boundary data in 2020, though the data development effort began years earlier. The dataset began as only point locations of water systems and was informally expanded to service area boundaries when the agency realized the need for estimating population projections and future water supply and demand. As seen in many other states, when DWR staff started requesting service area boundaries from water systems, many complied with little pushback. The data received varied in format, from ArcGIS and AutoCAD files to lists of addresses and highlights on town maps. DWR’s work is aided by the support of the Division of Water Rights and the Division of Drinking Water, though the mapping work is not institutionalized in either sister agency. Their involvement is especially helpful as they, unlike DWR, are regulatory agencies and DWRi physically visits approximately 60 systems each year and requests map updates during these visits. Utah’s geographic information work is also uniquely fortified by Utah’s geography division, created by legislation in the 1980’s. The geography division supported initial development of the service area boundary dataset, though DWR is now the official data steward. This data has largely been used internally by DWR and Water Rights, but these agencies receive frequent inquiries from researchers and graduate students to better understand and use the data. There is also an educational public service value to all the geographic data developed by state agencies, and Utah does a particularly good job at publishing all sorts of data for public use. Supporting the service area boundary work requires anywhere between $50-100k a year, which DWR thinks is likely done more efficiently within the government rather than through an independent contractor.

  • California’s efforts to develop their service area boundaries formally began with the creation of the Water Boundary Tool by Tracking California in 2012. The tool was initially funded by a grant from the CDC National Environmental Public Health Tracking Program, and water system managers could use the tool to draw their service area boundary in a Google Earth type of interface. The California Office of Environmental Health Hazard Assessment (OEHHA) and the California Department of Public Health (CDPH) funded subsequent development of the tool and continued gathering of data to support California’s declaration of the human right to water. Water systems were not required to develop service area boundary data but did so on a voluntary basis. The data are now under the purview of the California State Water Resources Control Board under the name Service Area Boundary Layer. The data layer and a boundary updating tool are in continuous development. During a three year period under an OEHHA and CDPH interagency agreement, the tool maintenance and data collection budget averaged $131k per year. After a few years, this project/database was transferred to the California water board, where they now reach out directly to systems through email, digitize the files/images they are sent, and then confirm the boundaries with the system. California suggests that having at least one pair of eyes regulating the output is necessary to be confident in a “good enough” dataset. The service area boundary data are regularly used to connect addresses to water systems for excessive watering reports and in grant eligibility determinations. The boundary data are also instrumental in supporting the human right to water for regionalization studies and in the first of its kind statewide needs assessment in 2020-21 to determine the feasibility of different solutions for struggling water systems.

  • North Carolina is still in the process of improving the quality of their service area boundary data for publication and use by the state. After the 2007-08 drought, North Carolina adopted legislation to better understand water use throughout the state and improve planning for future drought scenarios. The legislation specified that water systems with more than 1,000 connections or serving more 3,300 people needed to provide more water use information to the Department of Environmental Quality, though the DEQ was given discretion about what exact data to request. Among other requirements, the DEQ requested service area boundary maps, though, like other states, they did not specify a format for the maps. There is no penalty for failing to provide a water service area map to the state, but roughly 90% of systems made an effort to provide maps when requested. The collected maps were scanned when necessary and stored until 2018, when the DEQ collaborated with a research group at Duke University to turn the images into interactive GIS files. The university group had its own external funding to digitize the service area boundary data but coordinated with the NCDEQ to develop the maps to the standards of the state. The Division of Water Resources has managed this process, but DEQ representatives recommended working with other agencies or divisions when tackling such a project, despite the difficulties of interagency collaboration. Such collaborations can help avoid duplicative work and sometimes find additional funding sources for data development. Though the North Carolina dataset is still in development, it will be used for water supply and population projections, emergency planning and notifications, and to better identify areas served by domestic wells or with water quality issues that need further state investment.

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The Environmental Policy Innovation Center believes that technology can accelerate environmental progress and promote equity. To realize this promise, government agencies need the right people, policies, processes, and tools to solve environmental challenges. Water Service Area Boundaries are just one of these tools. 

The Environmental Policy Innovation Center built a technology program to help government agencies who want to work at the cross-section of environmental outcomes and innovation. With our partners, we work to:

  • Strengthen government’s capacity to develop or use technology;

  • Improve technology policies and processes to accelerate environmental solutions, center community experience, and encourage co-creation processes; and 

  • Create data and tools that enable community engagement.

Support for this work was received from the Bezos Earth Fund.

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