Dear Dan: In the case of my water source heat pump, we are using water from our spring, which is discharged in to a creek. The flow required is six gallons per minute , so the creek is not noticeably altered. I suppose if a large number of folks did the same, the temperature of the creek might fall a bit, but we are not talking about a huge drop in temperature. Where wells are used to both pick up and discharge the water, I doubt that the ground water would be cooled in winter to a significant degree, as the earth is quite a large heat sink. I suppose we could all go back in to caves, but if the country's population all went to caves, our presence under ground would no doubt heat up the earth's crust?
Yours Truly, Clifford Wilson [Non-text portions of this message have been removed]