The only change in the water after it's used by the heat pump is a slight increase or decrease in temperature. In some localities, all or parts of the installation may be subject to local ordinances, codes, covenants or licensing requirements. Check with local authorities to determine if any restrictions apply in your area. Closed-loop systems are becoming most common. There are 5 types of closed loop systems.
All types use a continuous loop where the heat transfer fluid is circulated.
A horizontal loop is usually the most cost effective when adequate yard space is available and trenches are easy to dig. Using trenchers or backhoes digging trenches three to six feet below the ground, you then lay a series of parallel plastic pipes. The trench is then back filled, taking care not to allow sharp rocks or debris to damage the pipe. A typical horizontal loop will have 400-600 feet of pipe per ton of heating and cooling capacity. Vertical loops are preferred in many installations where yard space is insufficient and where preservation of existing landscaping is desirable.