Hi Susan,

Thank you for contacting the UNH Extension Yard and Garden Infoline with your question about using unfiltered water that is contaminated by arsenic to water your vegetable garden.  It is generally considered unsafe to use water to irrigate vegetables that has a concentration of arsenic of 100 parts per billion or greater.

See this question that was asked of UMaine Extension. It has links to other resources on the subject as well-

https://extension.umaine.edu/gardening/2022/01/10/safety-of-watering-with-arsenic-in-well-water/

I hope this helps, and please ask if you have any further questions.

Information from soil testing lab -

The soil lab does have an arsenic test in terms of testing soil, however, for a comprehensive assessment on overall chemicals in soil - this would be a test from a private lab in NH, not UNH Extension.  Below is a link to the UNH soil lab webpage.

https://extension.unh.edu/agriculture-gardens/pest-disease-growing-tools/soil-testing-services

I recommend contacting the New Hampshire Department of Environmental Services (NHDES) for further guidance. They can provide the most accurate and up-to-date information on using your specific well water for irrigation, considering your crops, soil, and irrigation methods. You can find their contact information in the attached fact sheet.

FOR MORE INFORMATION
Contact the Drinking Water and Groundwater Bureau at<personal data hidden> or <personal data hidden>, or at des.nh.gov. You may also input your water test results to the NHDES Be Well Informed water treatment.

https://www.des.nh.gov/sites/g/files/ehbemt341/files/documents/2020-01/dwgb-3-2.pdf