Oregon Institute of Technology (OIT) is located on a hill, which gently slopes from the east to the west, in the north- east part of Klamath Falls. The campus has been using geothermal water, for its heating and domestic hot water needs, since it was relocated to this location in 1964. It has been in continuous operation for 35 years and now heats 11 buildings (~600,000 ft2 / 55,700 m2). It is the oldest of the modern geothermal district-heating systems, and due to the lack of experience with the design of large systems in the early 1960s, it has experienced some difficulties through the years. These difficulties have been resolved and the experience has provided a substantial body of information concerning the applicability of various materials and designs for low-temperature use