The Minnesota Department of Agriculture has assembled Tables of Laboratories, Analytical Capabilities and Contact Information (PDF: 55 KB / 2 pages) to help guide well owners in understanding the strengths and limitations of various testing services offered by commercial laboratories.
Minnesota’s current guidelines for pesticides in drinking water products were developed by the Department of Health. While recognizing that the immunoassay screens should only be viewed as indicators of contamination, and that they do not provide reliable concentration results for purposes of health risk assessment, you can compare the results of immunoassay screens, and of quantitative tests and analyses against the Department of Health drinking water guidelines.
Many private well owners begin by conducting an inexpensive immunoassay screen. A positive immunoassay screen result may be reason to repeat the screen to confirm the first set of results. It may also be reason to consider moderate-cost quantitative tests, or high-cost, certified quantitative analysis. Additionally, a well owner may want to install a home water treatment unit (see below) to address any health concerns. Well condition, age, location, construction method, geologic setting and proximity to contaminants are all factors that can affect drinking water safety.
If the results of testing your private drinking water well lead to concerns about exposure and health effects, you may want to install a home water treatment unit. These are known as “point-of-use” devices because they are designed to treat small amounts of drinking water for use in the home. The Minnesota Department of Health has developed a helpful webpage for those considering point-of-use devices for home water treatment.
Pesticide & Fertilizer Management Division