Generally, the average system will use 6 to 10 gpm while operating. This selection process should include a discussion with a licensed well driller and geologist to determine if sufficient groundwater resources are available for your project need. The production well could be your domestic water well, but it is critical that the well capacity, pump size, piping, and plumbing are enlarged to handle the additional flow. Poor water quality can cause serious problems in open-loop systems. Your water should be tested for pH, hardness, total dissolved solids, alkalinity, iron, manganese, conductivity, saturation index and other parameters depending on your location.
Mineral deposits can build-up inside the heat pump's heat exchanger.
Sometimes a periodic cleaning with a mild acid solution is all that's needed to remove the mineral scale. If your water has a high iron or manganese content you should be sure that the discharge water is not excessively aerated before it's injected into a return well. In some cases, the water needs to be pretreated. Finally, you should not consider using water from a spring, pond, river, or lake as the source for your heat pump system. If this option is selected, it would be advisable to evaluate the changes in the water quality and install a purification system to remove particles and organic material.