Your well was required to be tested when it was first installed, but what about after that? You are the owner of your water system, and it is your responsibility to protect your drinking water quality and the groundwater source.
Standard water quality concerns for private wells include coliform bacteria, nitrate, nitrite, fluoride, chloride, sulfate, sodium, hardness, and metals like aluminum, antimony, arsenic, boron, cadmium, chromium, copper, lead, iron, manganese, mercury, selenium, uranium, and zinc.