Here is the WI site. Look on your state and county sites. I also asked the testing labs for the list of all contaminants they could test for.
I worked in environmental law on hazardous waste issues. Worked on cases with Mercury, PCBs, and thousands of hazardous industrial chemicals in river systems, groundwater and fractured bedrock. Wished I had taken more science...
In WI the well information is public record and you should request it from the seller. We have our well tested annually.
For our well, We tested for about 10 hearvy metals, including arsenic, all the standard items, nitrites, nitrates, at least 10 farm related pesticides, herbicides, and such. Have your well tested for everything the Public Water Systems in your state must test for. I also looked up every "Superfund" site in WI (Federal and similarly listed State sites) to make sure I knew where they were in relation to our aquifer.
Here is a quote from a great WDNR site listing a ton of those we tested for.
"How can I find out if my water is safe to drink?
All public water systems are required to notify consumers if any contaminant, including pesticides, is detected at concentrations above the maximum contaminant level (MCL). In addition, public water systems that serve residential populations are required to complete a Consumer Confidence Report (CCR) each year. If you would like to view your community’s CCR, contact your local water supplier or visit the Wisconsin Department of Natural Resources (DNR) website at dnr.wi.gov.
Private well owners are responsible for the safety of their own water supply. As always, if you notice a change in taste, color or odor, you may want to use an alternate safe drinking water source until you can have your water tested. In addition, private well owners should have their water tested if they suspect pesticide contamination. There are a number of laboratories statewide that can provide drinking water sampling materials and instruction. A list of certified labs is available online at dnr.wi.gov or check your local yellow pages. What pesticides are most frequently found in contaminated drinking water? Based on Department of Agriculture, Trade and Consumer Protection monitoring surveys, the most frequently detected pesticides in Wisconsin are: Chemical breakdown products of metolachlor (Dual). Atrazine and its chemical breakdown products. Chemical breakdown products of alachlor (Lasso)"
https://dnr.wi.gov/files/pdf/pubs/DG/DG0007.pdfHope this helps.