Private Well Protection Study

Project Details by Fiscal Year
2014 Fiscal Year Funding Amount
$325,000
2015 Fiscal Year Funding Amount
$325,000
2017 Fiscal Year Funding Amount
$325,000
2018 Fiscal Year Funding Amount
$400,000
Fund Source
Clean Water Fund
Recipient
Minnesota Department of Health
Recipient Type
State Government
Status
In Progress
Start Date
July 2013
End Date
April 2018
Activity Type
Analysis/Interpretation
Assessment/Evaluation
Research
Counties Affected
Anoka
Becker
Carlton
Carver
Clay
Hennepin
Mahnomen
McLeod
Meeker
Norman
Otter Tail
Sherburne
St. Louis
Wilkin
Wright
Legal Citation / Subdivision
MN Law 2013 Chapter 137 Article 2 Section 8(e)
Appropriation Language

$325,000 the first year and $325,000 the second year are for studying the occurence and magnitude of contaminiants in private wells and developing guidance to ensure that new well placement minimizes the potential for risks in cooperation with the commissioner of agriculture.

2014 Fiscal Year Funding Amount
$325,000
Number of full time equivalents funded
1
Proposed Measurable Outcome(s)

Sample 200 - 205 newly constructed private water-supply wells by July 2015.

Measurable Outcome(s)

Sampled 19 newly constructed private water-supply wells.

Legal Citation / Subdivision
MN Law 2013 Chapter 137 Article 2 Section 8(e)
Appropriation Language

$325,000 the first year and $325,000 the second year are for studying the occurrence and magnitude of contaminants in private wells and developing guidance to ensure that new well placement minimizes the potential for risks in cooperation with the commissioner of agriculture.

2015 Fiscal Year Funding Amount
$325,000
Number of full time equivalents funded
1
Proposed Measurable Outcome(s)

• Track arsenic concentrations in new wells for a year after construction to see if water chemistry stabilizes.
• Sample 125 newly constructed private water-supply wells by June 2015.
• Determine how water sampling methods and the timing of collecting water samples contribute to arsenic test results in a new well.
• Identify the conditions that control arsenic occurrence in groundwater.

Measurable Outcome(s)

Sampled 162 newly constructed private water-supply wells.

Legal Citation / Subdivision
MN Law 2015 Chapter 2 Article 2 Section 8(e)
Appropriation Language

$325,000 the first year and $325,000 the second year are for studying the occurrence and magnitude of contaminants in private wells and developing guidance to ensure that new well placement minimizes the potential for risks in cooperation with the commissioner of agriculture.

Number of full time equivalents funded
1
Proposed Measurable Outcome(s)

• Finish all water sample collection.
• Perform statistical analysis on data.
• Track arsenic concentrations in new wells for a year after construction to see if water chemistry stabilizes.
• Study how water sampling methods and the timing of collecting water samples contribute to arsenic test results in a new well.
• Study the conditions that control arsenic occurrence in groundwater.
• Develop guidance for well contractors and private well owners to reduce risks from arsenic in well water.

Measurable Outcome(s)

• Collected an additional 129 initial water samples for new wells, for a total of 254 wells.
• Collected 252 water samples 3-6 months after the initial water samples were collected.
• Collected 136 water samples 12 months after the initial water samples were collected.

Legal Citation / Subdivision
MN Law 2015 Chapter 2 Article 2 Section 8(e)
Appropriation Language

$325,000 the first year and $325,000 the second year are for studying the occurrence and magnitude of contaminants in private wells and developing guidance to ensure that new well placement minimizes the potential for risks in cooperation with the commissioner of agriculture.

2017 Fiscal Year Funding Amount
$325,000
Number of full time equivalents funded
1
Proposed Measurable Outcome(s)

• Finish collecting the final 12-month water samples.
• Perform statistical analysis on data.
• Continue to track arsenic concentrations in new wells for a year after they are constructed to see if water chemistry stabilizes.
• Determine how water sampling methods and the timing of sample collection contribute to arsenic test results in a new well.
• Identify the conditions that control arsenic occurrence in groundwater.

Measurable Outcome(s)

• Collected 109 water samples 12 months after the initial water samples were collected.
• Started statistical analysis.

Legal Citation / Subdivision
MN Law 2017, Chapter 91, Article 2, Section 8(e)
Appropriation Language

$400,000 the first year and $400,000 the second year are for studying the occurrence and magnitude of contaminants in private wells and developing guidance and outreach to reduce risks to private-well owners.

2018 Fiscal Year Funding Amount
$400,000
Number of full time equivalents funded
1
Proposed Measurable Outcome(s)
  • Finish statistical analysis for data.
  • Present study results at state and national conferences.
  • Publish two journal articles, one is accepted for publication in Groundwater journal in March 2018.
Measurable Outcome(s)
  • Results of the statistical analysis are as follows:
    • Filtering can make a significant difference in samples that were elevated then reduced in arsenic concentration a year later.
    • Arsenic concentrations stabilize 3 to 6 months after well construction.
    • Collecting samples at least 6 months after the well is drilled will give a more representative result of the long-term concentration.
    • Collection of samples from plumbing rather than from the drill rig will give a more representative result.
    •  Arsenic concentrations will not necessarily decrease with time, half the time it may increase a year later.
    • Recommendation is for the homeowner to collect one more arsenic sample in the life of the well to verify the arsenic result, once the well has stabilized, at least 6 months afterward.
  • Presented the study's results at the Geological Society of America in Seattle, WA in October 2017
  • The National Groundwater Association accepted the arsenic variability article and can be viewed online at http://onlinelibrary.wiley.com/doi/10.1111/gwat.12643/full.
  • Will present the study’s results at the Geological Society of America – North-Central Section, 52nd Annual Meeting in Ames, Iowa in April 2018
Project Overview

Arsenic occurs naturally in soil and minerals and is commonly found in groundwater throughout much of Minnesota. The occurrence and distribution of arsenic in groundwater is difficult to predict. Research is steadily increasing our understanding of the mechanisms and geologic conditions that determine arsenic occurrence in groundwater. The arsenic concentration in a new well, measured at the time of construction, is sometimes higher or lower, compared to subsequent sampling results. It is not clear if these results reflect natural processes or are influenced by well construction and development methods and if the initial sample is truly representative of arsenic for that new well. Accurate well water quality data enables well owners to better assess health risks and avoid spending money treating well water that may not need special treatment, or believing their well water is safe and consuming water with arsenic levels that are a concern for health.

For this study, approximately 250 new water supply wells were sampled three times over a year for arsenic and other parameters. Wells were chosen based on different well contractors’ water sampling protocols for testing well water, as well as factoring in different well development methods. Most wells sampled were located in areas of elevated arsenic concentrations. The goals of this study are to:

  • Analyze different water sampling protocols used by well contractors to determine how arsenic concentrations may be affected.
  • Track any variation in arsenic concentrations for a new well over the year following construction.
About the Issue

Private wells supply drinking water for about 1.1 million Minnesotans; 20% of the population. Private wells are required to be sampled for nitrate, arsenic and bacteria only when newly constructed. Most wells are never re-sampled for these or any other contaminants following the initial sampling. Even for wells that are tested, there is no requirement that the water from private wells meet drinking water standards. Water test results from newly constructed wells indicate, as of August 2013, approximately 10.5% exceed the arsenic standard for safe drinking water. Public water supplies must meet drinking water standards, not private wells. The only requirement for the water from new private water-supply wells is to test negative for bacteria before they are used.

Project Details

This project will use existing private well monitoring networks and existing data from a variety of sources. It will also be supplemented by targeted well sampling to characterize the occurrence and magnitude of contaminants in private wells.

Guidance will be developed for state-licensed well contractors if it is determined that well placement and specific construction practices can minimize potential risks to people’s health by reducing arsenic levels.

Outreach and education efforts will be developed for well owners to increase their ability to identify and address potential well issues. Outreach activities will include water testing recommendations, well maintenance, and water treatment for specific contaminants and other water quality issues.

Project Manager
First Name
Emily
Last Name
Berquist
Organization Name
Minnesota Department of Health
Street Address
625 Robert Street North
City
St. Paul
State
MN
Zip Code
55155-2538
Phone
651-201-4594
Email
emily.berquist@state.mn.us