Source Water
 Source Water Tracker - houses SWP plans, Phase 1 assessments, groundwater investigations, contact information, and other SWP efforts that communities have gone through to protect their drinking water.
 Source Water Mapper - is designed to show spatially, an online version of the community's Phase 1 assessment, including an inventory of wells and contaminants. It lists most major programs and contaminants, with detailed location information throughout the state and links to existing databases.
  Block diagram showing 2-year capture zones

The term “Source Water” is used to define drinking water in its original environment,
either at the land surface or below the ground, before being treated and distributed by a water system.

The concept of Source Water Protection is that carefully managing the land which drinking water travels through leads to increased natural water quality and better protection of the resource (see diagram above). These protection efforts save the community money through less treatment and less likelihood of well replacement. Also, these efforts will decrease the likelihood of a catastrophe, such as a contaminant spill, taking away your water source.
The Non-Targeted Source Water Protection Program provides initial Source Water Assessments for all Community Water Supplies in Iowa and works with communities that decide to proactively protect their drinking water source, either independently or with the assistance of a contractor. The program strives to protect all public drinking water from contamination, and is divided into three different phases:

  1. The 'Phase 1' assessment. Provided at no cost to the water supply by the state, these assessments detail the water system’s active wells, source water areas, susceptibility, and known potential contaminants.
  2. The Source Water Plan. If a community decides to protect its drinking water, it is encouraged to write a Source Water Plan. These plans detail how the system will start to protect its drinking water resource.
  3. Implementation. After the plan has been submitted, a community can start to implement the items listed in the plan. 

    The development of a good SWP Plan doesn’t require any assistance or involvement of an engineer or consultant. However, most often we find that municipalities do not have much experience with these kinds of projects, and  may find it useful to contact an outside entity for assistance. Additionally, the Iowa Rural Water Association provides experienced source water consultation and assistance for developing SWP plans at no charge to the public water supply. The Iowa Association of Municipal Utilities can also help with source water plans.

    Map of Iowa Rural Water Association assisted communities with submitted and approved SWP plans since 2007
Links to Community Source Water Plans completed by the Iowa Rural Water Association in 2014 -



Statewide Susceptibility Map - The determination of susceptibility recognizes that certain aquifers are better protected than others. Research has shown that subsurface layers that impede the movement of water, such as clay, till, or shale, can be used to estimate the probability of contaminants entering the aquifer. For this reason the source water program has designated four categories of susceptibility based on the cumulative confining layer thickness above the aquifer.   

Confining layer thickness Susceptibility designation:

<25 feet Highly susceptible
25 to 50 feet Susceptible
50 to 100 feet Slightly susceptible
>100 feet Low susceptibility

Information on each of Iowa’s 1,900 public water systems, including wells, production, protection, and history can be found via the Source Water Tracker and Source Water Mapper application links at the top right of the page.

Source Water Planning Guides

  • Source Water Protection Guidebook details the seven steps needed for source water protection in Iowa; where to go for assistance, and what information is available. Each of the steps listed in the document are vital for increased confidence that your water will be safe and plentiful for years to come. Provided in the guide are informational web links, examples, lists of potential contacts, and helpful tools to make source water planning as easy as possible.
  • Source Water Protection Workbook contains form-fillable worksheets and checklists designed to help with meeting preparation, work assigned, schedules and deliverables. Also included are informational web links, an introduction to Geographic Information Systems (GIS) resources as a tool to help with contaminant and well inventories, and contact information for members of the Source Water Advisory Group (SWAG).
  • Geographic Information Systems (GIS) Resources includes  links to GIS vocabulary terms, GIS training materials, a listing of Iowa GIS layers, the Iowa DNR and USDA GIS libraries, a comparison of GIS software, and the Iowa State University Geospatial Technology Program.
 Non-Targeted Systems Contact
 Targeted Systems Contact
 Bob Rowden
Jeff Vansteenburg