Wellhead Protection Section
Heat Pumps

One of the newer industries to start in Missouri is the construction of ground source heat pump systems. These systems are designed to heat or cool a house or structure by using the earth's constant ground temperature. During the winter the outside air temperature may average about 20 degrees Fahrenheit; however, groundwater stays an average of 55 degrees Fahrenheit. The idea of a ground source heat pump system is to pump groundwater from a well (open-hole system), or an approved fluid from a buried loop (closed loop system) through a heat exchange unit. The heat exchange unit will extract heat from the fluid to heat up your home in the winter or add heat to the fluid in the summer to cool your home.

There are three main types of systems installed: the horizontal closed loop system, the vertical closed loop system, and the open loop system. The closed loop systems use a loop of heat fused polyethylene or polybutylene pipe. The pipe is laid in trenches (horizontal system) or put down boreholes (vertical system), connected to the heat exchange unit, and filled with an approved heat exchange fluid. These approved fluids include pure glycerine solution, food grade propylene glycol, dipotassium phosphate, sodium chloride, potassium acetate, methanol, water, or ethanol. The horizontal systems were only regulated from January 1994 to August 1996. There were construction rules for this type of system if the horizontal system was constructed during this time period, otherwise these systems are exempt for our rules unless over 10 feet in depth. The vertical system has a depth limitation of 200 feet. If there is a situation where a system needs to be installed to a depth greater than 200 feet, you will need to contact us.

The open loop system uses a domestic water well to supply groundwater to the heat exchange unit. The water is either pumped back into the ground through a second well or to a surface lake or pond. Keep in mind that if you are disposing of this water to the surface it must remain on the landowner's property. It may not be run to drainage that leaves the property unless applicable permits are obtained through the Water Pollution Control Branch, Water Protection Program, Water Protection and Soil Conservation Division.