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Status: The water tool is functioning normally.

Water Boundary Tool

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California Environmental Health Tracking Program

850 Marina Bay Pkwy, P-3
Richmond, CA 94804

(510) 620-3038
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Last Edited: 6/18/2013

Frequently Asked Questions

Below are some Frequently Asked Questions about the Water Systems Geographic Reporting Tool.  For step-by-step instructions on how to use the tool, see Instructions and Tutorials.

General background

Benefits of participation

Details about using the tool

Getting started

Why was this tool developed?

There is no complete map of public water systems for California, and accurate digital maps of the customer service areas are available for only a few of the 8000-plus public water systems in California.  Many water systems lack digital files of their customer service areas, while in other cases, there may be multiple versions of boundaries for a single water system. 


This tool was developed to facilite the creation, collection, and vetting of digital maps for every public water system in California.  This in turn will enable the creation of an accurate, complete map of the all public water system customer service area boundaries in California as they change over time.  The reasons this effort is important are described below.


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Who is funding and developing the tool?

The California Environmental Health Tracking Program (CEHTP) initiated this effort; developed, deployed, and maintains the tool; and hosts the website.  This work was funded by the Centers for Disease Control and Prevention (CDC).


The Information Center for the Environment (ICE) at the University of California at Davis is conducting outreach to water systems and is pre-populating the tool with boundary files obtained by them from various sources.  This work is funded by the Drinking Water Program of the CA Department of Public Health. 


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 Are the boundary files available for public viewing or use?

Yes.  All water system boundary files created using the Water Tool are collected in our drinking water system service area database.  The database is updated on a continual basis as changes are made to these files.  These data are available as a public use dataset for the state.  You can also view boundaries for individual water systems.  Registration is not required to view or download these data.  Please note that these data are subject to change as public water systems continue to input and edit their customer service area boundaries.


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If I use the boundary files, who should I cite?

We request that you cite the California Environmental Health Tracking Program or link to the CEHTP website when reporting results that are derived from the service area boundaries managed by the Water Boundary Tool. 


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What enhancements are expected in the future?

We are planning a number of enhancements to the Water Boundary Tool in the next year.  Listed below in order of priority are the new functions that we will implement:

  • View neighboring service areas -- While you are interactively editing your service area boundary, you will have the opportunity to toggle on and off the display of service area boundaries from neighboring water systems.  This will allow you to quickly determine areas that overlap with other water systems.
  • Donut holes -- If there are large areas in the middle of your water system that are not part of your service area, we will provide the tools to cut those areas out, like a donut hole.
  • Pressure zones -- If you keep track of pressure zones in your service area, we will give you the opportunity to either upload them or to create them interactively while editing your service area.

If you have other ideas for enhancements, please let us know.


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Why is my participation important?

Your participation is important because you have information about the customer service area of your water system.  This information is essential for creating a complete, accurate statewide map of water systems that will help California to:

  • Prepare for emergencies that may impact water systems, such as natural disasters, chemical spills, and other emergency situations
  • Conduct important research about the relationship between drinking water, the environment, and our health
  • Increase collaboration and communication between water systems and with other public utilities

Learn about how the water system boundary data have already been used to support public health in our Spring 2013 Newsletter.

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What will this tool do for me?

You can use this tool to:

  • Digitize your customer service area boundary and use the digitial file for your own needs.  Any data that you enter into the system can immediately be exported and viewed in Google Earth, Google Maps, or GIS software like ArcGIS.
  • Identify affected areas, mobilize and allocate resources, and contact neighboring water systems during emergencies
  • Better understand, analyze, and summarize information about the areas and populations you serve
  • Streamline your existing activities

LPA success story:  Kathe Barton of the Inyo County LPA used the tool to map most of the systems in her jurisdiction.  In just a few sessions, she created digital files for over 70 of the Inyo LPA systems.  She found it very easy to use the system and has already benefitted by exporting the maps and using them for water supply permits, sample siting plans, and LAFCO AB54 reporting requirements.


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What kind of information are you asking for?

Currently, we are asking water system and water district personnel to:

  • Register for the tool
  • Input customer service boundaries for your water systems by:
    • Drawing a boundary by using the tool's drawing functions or by selecting individual parcels or APNs 
    • Uploading a table of customer service addresses, which the tool will geocode and convert into a boundary
    • Uploading a table of coordinates, which the tool will convert into a boundary
    • Uploading digital files, such as KML files or zipped shapefiles
  • For water system personnel:  answer nine brief questions about the water systems that you manage and maintain

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What do you mean by "customer service area boundary"?

We are asking you to input your water system's customer service area boundary, which means all residential and commercial customer connections for which you have a permit to provide services and can bill payment.  For the purposes of this tool, a customer service area boundary does not include connections where you sell your water to another system.


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Are the files I'm providing a security concern?

No.  Providing this information is not a security concern. 


We only want to know the geographic area that your water system serves.  We are only asking you to input customer service area boundaries, which most water systems already provide to the public.  We are not collecting information on pipes, storage facilities, or other sensitive areas.  If you create your boundary by uploading customer addresses, the address data will remain secure and cannot be accessed by the public.


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How much effort will it take to input data?

In general, it should take very little effort to input data if you:

  • Have your water system boundary information in KML or zipped shapefile format
  • Have a table of customer addresses or coordinates

It may take more time and effort if you:

  • Represent more than one water system, in which case you will need to input data for each system
  • Are unsure of how your water system's service area is defined

There are a few additional requirements, depending on the type of user you are.  These should be of minimal effort. 

  • If you work for a water system, we will ask you to answer a short, nine-question survey that should take less than a minute to fill out.
  • If you work for a district engineer or local primacy agency, you will be responsible for authorizing requests for individuals to edit water systems within your jurisdiction.  Reading email requests and clicking approval/rejection links should require minimal effort.

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Who is allowed to edit the boundary for my water system?

The service area bounday files for any given water system can only be edited by individuals who are approved for that water system.  Below are the user categories, along with their corresponding level of access/jurisdiction. 

  • Water system staff – can create and edit boundaries for their water system; can mark boundary files as completed
  • Water system wholeseller staff – can create and edit boundaries for all member water systems; can mark boundary files as completed
  • District engineer / local primacy agency (LPA) staff – can create and edit boundaries for all water systems within their district / jurisdiction; can verify completed boundary files
  • State engineer / admin staff – can create and edit boundaries for all water systems

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Why are there already boundaries inputted for my water system?

CEHTP and our partners inputted data for the water systems for which we already had digital maps of boundaries.   However, these may not be the most accurate or recent files.  Therefore, you are encouraged to register and edit these boundaries or create your own. 


The tool was designed to maximize collaborative potential.  Multiple boundaries can be saved for a single water system.  These boundaries can be reviewed and edited by all users authorized for that water system, allowing multiple users to engage in a process to create and select the most accurate file.


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What do I need to do before I begin?

To edit a service area boundary for the water systems in your jurisdiction, you need to be registered at the Water Boundary Tool first.

Most users of the Water Boundary Tool will also be users of the Electronic Annual Reporting (EAR) System at the DRINC portal (  EAR user accounts and privileges are automatically extended to the Water Boundary Tool.  Use this link to sign-in at EAR and then follow the links back to the Water Boundary Tool. Watch the video tutorial below or download this set of screenshots for what to expect when using the DRINC portal to sign-in.

If you are not a DRINC/EAR user, then you will need an account through the Water Boundary Tool's simple registration process.  After your registration has been approved, you will receive an email with your login and password.  Then you may begin using the tools to create and edit your water system boundaries.


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How do I start editing my water system's service area file(s)?

Once you've registered and signed-in, click the "Begin using tool" button near the top of the Water Boundary Tool's home page.  On the following page, all of the water systems that you are authorized to edit will be listed.  For the water system of interest, click the "Create/Edit/Manage Service Area Files" link that appears below the survey questions.  You may have to click a plus sign (+) next to the water system's name to expand detail about the water system.  If you're a water system user, see this set of screenshots for what to expect.  If you're a District, LPA, or State Admin user, see this set of screenshots.


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How do I import boundaries for multiple water systems from one shapefile?

Many agencies and organizations, like wholesellers and local primacy agencies (i.e. counties), have GIS expertise and already maintain service areas for water systems in their jurisdiction.  For these users, we have developed the Shapefile Conflation and Import Utility (link displays, if you're signed-in), which does the following:


1) Adds a Public Water System ID (PWSID) to each record-  First, this will take your existing shapefile and assist you in quickly adding a Public Water System ID (PWSID) to each record.  The PWSID field is important because it is the unique record locator that the California Department of Public Health uses to keep track of permitted Public Water Systems.  The utility will help you quickly match the water system names in your shapefile to the water system names that we have on file, adding a PWSID to your shapefile in the process.  Once you're done, you can take your shapefile back to your jurisdiction.  You can maintain the PWSID field in your local service area database to avoid this step the next time you come to this website.


2) Import each service area- Next, you can import each of the service areas into our database.  Before importing, you will have the opportunity to compare a map of your boundaries to any existing ones that we have in our database.  After selecting the service areas that you'd like to import, the utility imports each of your selected service areas into our database.


If you have been asked by a tool administrator to submit your shapefile, and that person will run the Shapefile Import utility on your behalf, please use the File Manager (link displays, if you're signed-in) to upload your zipped/compressed shapefile to our servers.


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How do I construct a service area boundary from individual properties?

If your service area is defined completely (or in part) by individual property boundaries (also known as "parcels"), the tool allows you to select individual properties to create or add to your service area.  This is particularly useful for small water systems comprising less than 100 properties.  The tool uses a large statewide layer of geographic boundaries provided by county assessors' offices, from which you can interactively select property boundaries in a map and/or from a list of assessor parcel numbers (APNs).  Our property database covers 56 out of 58 counties in CA; Orange County and San Luis Obispo county are not currently available.  Please see this set of screenshots for a detailed explanation of how to construct your service area from property boundaries. 


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How do I add new areas to an existing service area file?

If you need to add additional polygonal sub-areas to your existing service area file, click the "More Tools/Options..." link in the service area editor (see this tutorial to learn how to begin editing a service area file).  In the menu that pops up, choose "Add Polygon...".  Follow the instructions that appear in the right hand table of contents.  If you make a mistake, you can cancel out of the utility without saving.  If you've already saved the new polygon, but you want to delete it, click all of the nodes of the polygon to delete them.  Once there are less than 3 nodes left, the polygon can be completely removed from the map.

The new polygon that you add to the service area file can be non-contiguous with the existing polygon(s) in the service area file.  In other words, the new polygon doesn't have to overlap or touch the existing polygon(s).  However, if you choose to create a new polygon that overlaps with the existing polygon(s), consider also using the More Tools/Options --> Merge Overlapping Polygons utility to combine the overlapping or touching areas into a single contiguous polygon.

For more detail on each of these operations and for visuals of what to expect, see this set of screenshots.


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Can I still edit a boundary after I've marked it complete?

 Marking a boundary as "complete" makes it available to District Engineers and LPA staff for verification.  If your boundary hasn't yet been marked "verified", then you can still make edits.  If you are making changes to reflect a new update to your boundary, please create a new file and indicate the Valid From and Valid To dates. 


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Under what circumstances should I specify the Valid From and Valid To dates for each boundary?

Water system service areas can change over time.  Some common ways they can change are through the addition of new building developments, consolidations, or changes in ownership.

The Water Boundary Tool enables you to enter the time period for which the boundary applies (called “Valid From” and “Valid To”), which will help you to keep track of changes to your water system service area over time.  This information is also very important for enabling future scientific research, so we recommend that you create a new file for each update that occurs (versus editing an existing file).


Guidelines and Suggestions:

  • When to create a new file:  Create a new boundary file when a change occurs to your service area boundary.  Specify the time period for which the boundary applies by filling in the “Valid From” and “Valid To” dates when saving the file.  This time period should be mutually exclusive from the time period of any other boundary file.  Also, remember to change the “Valid To” date of the previous boundary file so that it is one day earlier than the “Valid From” date of this new boundary file.
  • Specificity:  We are trying to track changes at a monthly or annual scale, so there is no need to make separate files to characterize daily changes.  For example, instead of creating a new file for each new connection brought online in a large housing development, wait until the development project is finished.  Then create a new boundary file with a “Valid From” date that is approximate to the project completion date.   
  • Determining the "Valid From" date:  The “Valid From” date should reflect your best estimate of the starting date of the time period for which the boundary is valid.  It does not need to be exact.  If you only have one boundary file entered for your water system, and you are unsure of the starting date that the service area was valid, then leave this blank.
  • Determining the "Valid To" date:  The “Valid To” date should reflect your best estimate of the ending date of the time period for which the boundary is valid.  In nearly all cases, you should only enter a value for the “Valid To” date of a boundary file if there is another file reflecting a more current boundary.  If you only have one boundary file entered for your water system, and you are unsure of the ending date that the service area was valid, then leave this blank.
  • When to leave both the Valid To/From dates blank: If you only have one service area file entered into the system, then you should likely leave both the Valid To and Valid From dates blank.  Since there are no other files in the system, there will be no conflicting validity periods.  Moreover, if you only have one service area file entered into the system, you should only enter a Valid From date, if you know for sure that the geographic area wasn't applicable before that date, like, for instance, the date your water system came into existence and no other changes in the service area have occurred since that date.


Valid From Valid To Created By Created Edited By Edited Status
 1/1/2012    Smith  1/1/2012  Smith  1/1/2012  
 1/1/2011  12/31/2011  Smith  1/1/2011  Smith  1/1/2012  
   12/31/2010  Smith  1/1/2010  Smith  1/1/2011  

Things to note:
  • The most current file does not specify a “Valid To” (ending) date
  • The middle file specifies both a “Valid From” (starting) date and a “Valid To” date
  • The file for the oldest boundary does not need to specify a “Valid From” date
  • There is no overlap among the time periods of the three files (e.g., the “Valid To” date of the last file is one day earlier than the “Valid From” date of the next file)

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