Poor water quality will cause serious problems in open-loop applications. Your water should be tested for hardness, acidity and iron content before the heat pump is installed. Poor water quality can cause mineral deposits to build up inside the heat pump heat exchanger and periodic cleaning will be required. Water from flowing springs, ponds, lakes or river sources are not recommended for heat pump use, unless proven to be free of excessive particulate and organic matter. These sediments will contaminate the heat exchanger heat pump system and make it inoperable.