Since 2005, the MSU Extension Well Educated program has provided water quality testing assistance to private well owners across Montana. Data from the program provides insights about what parameters (arsenic, nitrate, etc.) well owners may find in their groundwater in different parts of the state. Currently, data from the 2015 to 2023 program years has been currated into our database, which supports the information on this webpage. 

The map below has guidance on what to test for, based on location. You can test your water by contacting a certified lab (click here for certified lab list), or by visiting a county partner in the Well Educated Program (click here for Well Educated partner list). For a list of Well Educated testing packages and a parameter glossary, click here. 

Interactive Map

Click on your county in the to map below to view testing recommendations and parameters of concern in your area. The following three videos provide guidance on using this map.

1. Click here for a quick 2 minute overview of using the map

2. Click here for a 2.5 minute video overviewing testing guidance based on the Well Educated program results.

3. Click here for a 4 minute video for a slightly more detailed explanation of the testing guidance for sensitive groups based on counties and watersheds.

Statewide Parameters of Concern

MCL = Maximum Contaminant Level

All Parameters with Exceedances MCL Units
Arsenic 0.01 mg/L
Fluoride 4 mg/L
Nitrogen, Nitrate+Nitrite as N 10 mg/L
Selenium 0.05 mg/L
Uranium 0.03 mg/L
Lead* 0.015 mg/L
Copper* 1.3 mg/L
*Lead and copper typically come from plumbing fixtures rather than groundwater, however, corrosive groundwater can exacerbate the issue.

More information on individual parameters is available on our factsheet website (click here). 

Click here for a scientific paper on human health risk from Montana groundwater.