FAQ > Residential > What should I test for, and how often?
Search the FAQ for entries containing:
NH Department of Environmental Services (DES) recommends testing for bacteria and nitrate at least yearly. The best time to test is in the spring or summer when bacteria is most likely to occur. NH DES also recommends testing for radon and arsenic every 3-5 years.
For the full list of recommended testing please see NH DES Fact Sheet
