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Idaho Ground Water Quality

An interactive map of ground water quality conditions for Idaho's private well owners


The Idaho Department of Health and Welfare created the interactive map below to make private well owners aware of existing ground water quality data in their area and promote regular ground water quality testing. Ground water quality at privately owned wells is not regulated by the State of Idaho. Private well owners are responsible for maintaining their well and ensuring the water is safe to drink, which can be accomplished through periodic testing.

About the Map

Private wells displayed on the map were sampled by the  Idaho Department of Water Resources , the  Idaho Department of Environmental Quality , the  Idaho State Department of Agriculture , and  private well owners  between 2004-2020. Each well contains the most recent sampling results for up to nine chemicals, the year it was sampled, the sampling agency, and the well depth if it is known.

Agencies may have additional data that has not been included as part of this map. Additionally, more recent data may exist for certain chemicals that were unavailable at the time this map was published. Contact the individual sampling agencies for more information.

Find an Address or Locate on the Map

Navigate using the zoom controls or enter an address or place of interest in the search field panel at the top right of the map below. Additional information for each testing laboratory (red star) and well site (blue dot) is available by selecting the icons on the map.

Map published by the Idaho Department of Health and Welfare July 14, 2021. Data presented collected by the Idaho Department of Water Resources, Idaho Department of Environmental Quality and Idaho State Department of Agriculture, and private well owners between 2004-2020.

Why it is Important to Know What is in Your Well Water

Do you know where your drinking water comes from or what is in it? 30% of Idahoans have made private well water their primary source of water. Due to inadequate water testing, you may be exposed to ground water contaminants that pose health risks.  How long has it been since you had your well water tested? If you are a private well owner, you are responsible for ensuring that the well water is safe to drink!


A variety of contaminants, both naturally occurring and human-caused, can be found in Idaho’s groundwater. Depending on the contaminant and concentration, there can be short- and long-term health and developmental effects.  Testing your drinking water is the only way to know what’s in your water.  Once you know, then you can take steps to learn what is causing the contamination and determine the best treatment and maintenance options.  Key contaminants that every well owner should look for are:

  • Nitrates (lessens ability of blood to carry oxygen)

  • Bacteria like E. coli (nausea and diarrhea).

  • Arsenic (causes cancer and skin lesions)

  • Fluoride (stained teeth and bone pain/weakness) Fluoride at the optimal level of 0.7 mg/L -1.0 mg/L in drinking water, can prevent cavities and tooth decay. Fluoride more than 4.0 mg/L can be hazardous. 

  • Selenium (hair loss and circulation problems)

  • Uranium (kidney damage)

  • Lead


While your water may appear safe, harmful levels of contaminants occur at such low concentrations that they often cannot be tased, seen, or smelled.  This means regular testing and maintenance are necessary to protect the health of your family.  You should test your well water once a year for bacteria and nitrates and once every three to five years for everything else. Use the Groundwater Quality Near Me map to aid in determining what contaminants to test for. If undesirable levels of contaminants show up in your water, contact The Department of Health and Welfare’s Environmental Health Program at or 1-800-445-8647 to determine the best method to fix the problem and if you have questions about your well water testing results.

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