Homeowners who use private wells or cisterns as their source of drinking water should have the water tested annually. Water quality in private wells is not regulated by the EPA or the state. Homeowners who use private wells or cisterns need to contact a certified lab to have the water tested for bacteria and other contaminants, such as nitrates.
EPA does not regulate private wells for drinking water, but does offer helpful information.
CDC also offers guidance on maintenance, testing, treatment, and more.