Private Well Testing for Pesticide Contamination

Atrazine Private Well Screening Video

• Private well owners are responsible for testing their wells and for their own drinking water safety.
• When pesticides or their breakdown products are detected in Minnesota wells, the levels are usually very low and periodic testing is the only means of determining whether drinking water contains contaminants above Health Risk Limits set by the Minnesota Department of Health. For an example of drinking water well test results check out a report (PDF: 183 KB / 18 pages) from a special MDA private well screening program in southeast Minnesota.
• Pesticide contamination in private wells can be the result of homeowner activity (e.g., on-site septic systems, improper disposal of chemicals, poor well location or construction), or be the result of land use and other activities near or far from the well.

• Wells most at risk of pesticide contamination are:
  • Shallow, less than or near to 50 feet in depth.
  • Old, built prior to 1974.
  • Dug, drive point or bored wells.
  • Wells that are damaged.
  • Wells that are located close to areas of pesticide use or storage.
  • Wells located in geologically sensitive areas, an example being the sandy soil and limestone bedrock areas of central and southeastern Minnesota.  

Consult the Minnesota Department of Health’s Well Owner’s Handbook (PDF: 993 KB / 40 pages) pages 6-11 and the Private Well Contamination Risk factsheet for more information.

• Pesticide testing of private drinking water wells can be conducted by a laboratory at three different cost levels with different results or at home with a basic test kit.  This information can be found at the Private Well Pesticide Testing Options web page. 

There is no state agency program or office that is required to conduct routine sampling or analysis of Minnesota’s private drinking water wells for any type of contamination, including pesticides. Public drinking water supplies, however, are required by state and federal agencies to routinely test for several pesticides under Minnesota’s implementation of the Safe Drinking Water Act.

MDA Contacts

Joe Zachmann
651-201-6588
joseph.zachmann@state.mn.us

Pesticide & Fertilizer Management Division