It varies from state to state.  Some states require no training or qualifications at all for home inspectors.  In these states finding a reliable home inspector can be daunting.  In South Dakota the state requires home inspectors to be licensed with the state, and to complete a certain number of hours in continuing education each year in order to maintain a license.  Home inspectors in South Dakota have to meet certain educational requirements and then pass an exam on home construction and home inspection related material before becoming licensed.