This third edition was put together by an NGWA volunteer work group to provide updated information on the original Guidelines that was published by NGWA in 1997 and then updated again in 2009. The guidelines are written for loop well contractors, loop well design consultants, government officials, educators, students, and consumers. It is a stand-alone document that does not supersede regulations or standards, and provides details on issues related to the construction of vertical closed loop ground source heat pump systems and offers insights to practical resolutions of the issues.