How-To Guide: Part Five
Methodologies
Learn about best practices and methodology
for developing water service area boundaries.
States should adopt and promote technical requirements that facilitate the creation of water service area boundaries - let’s break down how.
Step One: Adopt a Common Definition of
“System Boundary”
Such a definition could include all parcels currently served directly; all parcels that would be served directly if they applied for a connection; parcels served by various resellers such as mobile home parks, operational subcontractors such as metering and billing companies. If data and resource availability constrains the ability to meet the same system boundary definition for all systems, boundary metadata should indicate what system boundary type is used for each system. For example, if parcels that are not currently served by the system are included, or if a wholesaler system boundary is shown to include the service areas of all customer retail service areas, these system boundaries should be categorized as “jurisdictional service areas.”
Step Two: Establish Geospatial Standards
This could include coordinate reference system, datum, and scale/ resolution. This should also include the geospatial file type for publishing and sharing. When compiled and shared publicly, boundaries should be shared in an open source file format, such as geojson or geopackage. Most systems will not have boundary data in a gis file, but a hierarchy of the data format should be used to start with the highest quality data possible. This will save time and reduce the introduction of errors as service area boundary maps are digitized.
Preferred data and file format are as follows:
Open source GIS file of service area boundary, such as geojson or geopackage
Proprietary GIS file of service area boundary, such as shapefile
GIS file of the location of water lines that can be used to estimate the service area boundary
Image of service area boundary, shared as a pdf, jpeg, png, or similar file
Image of water lines
List of address served by the water system, such as the list used for meter reading or billing
Verbal description of the service area
Step Three: Require Metadata
The most vital piece of metadata when collecting and sharing service area boundary data is the USEPA PWSID of the water system, but we recommend the following metadata to also be required:
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The coordinate reference system and projection for the GIS data
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PWSID - as {2-letter-state-code}{pwsid number} e.g. MA3035000
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The name of the water system e.g. Boston Water and Sewer Service Commission
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Data source - the type of data that the boundary was generated from, which can be one of:
Census Place
Image from Utility
Description from Utility
Water Lines
Layer from Utility
County boundary with other systems removed
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A URL detailing the dataset or organization where the information came from, if available.
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The email address for the person providing the file.
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The date that the contributed data was last updated by either the water system, contractor, or state regulator (YYYY-MM-DD)
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The date that the data was contributed (YYYY-MM-DD).
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Options for service area type should include:
Current_Service_Area: The collection of parcels whose buildings are served by a connection from the relevant pwsid
Waterline_Adjacent_Parcels: the collection of parcels whose buildings are approximated to be served by the relevant pwsid when the source data is a waterline map
Jurisdictional_Area_Extent: The collection of parcels that are required to be served by a connection on request/ payment of connection fee by the relevant pwsid
Jurisdictional_Area: The convex hull of Jurisdictional_Area minus known PWSIDs
Municipal_Boundary - use this when a census boundary is used to estimate the service area boundary, despite the municipal boundary and service area boundary not aligning perfectly
EPIC and partners have estimated service area boundaries for over 90% of community water systems, so states can get started by using the provisional national map as a starting point. There are also likely other state or local processes you have already in place to work with water utilities such that adding service area boundaries isn’t a big lift - for example, consider partnering with teams conducting sanitary surveys. Though agency personnel are likely overworked already, contacting systems through existing communication pathways will likely be more successful than having two new GIS employees contact every system.
Further, states should consider the number of community water systems in a state - and the relative capacity (time, technical knowhow) of those systems. It is likely larger systems will have a GIS file of their boundary or at least an image of their boundary. Smaller systems may have little to no data and more frequently lack the time or technical capacity to make maps themselves. With this capacity in mind, consider where partnerships are needed - see Planning & Partnership section.
Step Four: Consider What Data Exists & Capacity of Water Systems
Step Five: Select Tools
States have multiple avenues to help them develop the data and can evaluate what tool is best for their context via consultation with key partners.
For example, if approximate data is sufficient for the intended use, then a state can use EPIC's approximations via the [National Map]. States can also use this data as a baseline and add additional components for their internal use.
But if more accurate or precise data is needed (and in most instances, we think it is!) then a state should determine the tool that you would like to use to facilitate data development. As a general matter, EPIC advises against the creation of new tools from scratch since other tools are available and making their own tool would take much more time and money. That said, some states have successfully developed tools - for example, Texas developed the Texas Water Service Boundary Viewer for creating service area boundaries and allowing water system personnel to modify and update the boundaries over time.
Available tools include:
As part of their lead service line prediction software for water systems, BlueConduit enables water systems to easily update and refine their service area boundaries. With permission, this data can be added to the national map.
As part of their drinking water monitoring and management software for states, WaterSuite enables water systems to easily update and refine their service area boundaries. With permission, this data can be added to the national map.
Internet of Water Boundary Sync
Internet of Water created an open-source application that can be deployed in each state. This tool enables water systems to easily update their boundaries and state administrators to approve. To be released in Spring 2023.
Most systems will not have boundary data in a gis file, but a hierarchy of the data format should be used to request the highest quality data possible. This will save time and reduce the introduction of errors as service area boundary maps are digitized. Preferred data and file format in order of preference are as follows:
Open source GIS file of service area boundary, such as geojson or geopackage
Proprietary GIS file of service area boundary, such as shapefile
GIS file of the location of water lines that can be used to estimate the service area boundary
Image of service area boundary, shared as a pdf, jpeg, png, or similar file
Image of water lines
List of address served by the water system, such as the list used for meter reading or billing
Verbal description of the service area
Step Six: Request the highest quality existing data from community water systems
States can request information sharing on a voluntary basis. Many states have had high success rates with the voluntary submission of existing maps. Recognizing that every state will be different, EPIC developed a template that states can adapt and use for outreach purpose: Template for states to contact water systems.