of material having relatively high thermal conductivity the subsurface pipe system is preferably buried at an intermediate depth between the surface and the depth where constant temperature occurs in order to provide most of the benefits of a subsurface system while reducing the labor required to bury the pipe system application_number US 201213585323 A description the geothermal heat exchange system for a water supply is an open ended water supply system i e water is supplied from an external source to pass through the system the water being disposed of as wastewater after it is used the water passes through a subsurface pipe or network of pipes where the temperature of the water is adjusted substantially to that of the surrounding earth the system operates entirely by gravity flow from an elevated external source so that no pumps or power is required for its operation fig1 of the drawings is a schematic illustration of an exemplary geothermal heat exchange system for a water supply according to the present invention water is provided from an elevated storage tank or supply 10 e g a conventional hilltop or mountaintop water tank elevated water tower etc the water in the tank produces a pressure head 12 relative to the outlet of the system e g a dispensing fixture supply pipe 14 according to the elevation of the tank 10 above the outlet or dispensing fixture supply pipe 14 while the elevated water supply 10 is shown to be directly above the.