Input Sought on Standards for Geothermal Heat Exchange Wells

The California Department of Water Resources is beginning the process of updating the state’s standards for geothermal heat exchange wells, which utilize the earth’s internal capacity for heating and cooling.

In 1996, the Legislature added geothermal heat exchange wells (GHEW) to the well types included in the state well standards. DWR plan to update and finalize the 1999 Draft GHEW Standards by June 30, 2013, so the agency is planning to conduct a 30-day public comment period as well as public workshops in spring 2013.

For the purpose of protecting groundwater quality, the draft standards provide statewide minimum standards for the construction, maintenance, abandonment and destruction of GHEWS. The statewide standards also set the minimum standards for local well ordinances enforced by city, counties or water agencies.

According to the 1999 draft standards, geothermal heat exchange wells use “the heat exchange capacity of the earth for heating and cooling,” where the ambient ground temperature is 86 F or less. The wells “use a closed-loop fluid system to prevent the discharge or escape of its fluid into the surrounding aquifers or geologic formations.” These wells aren’t made to produce water or steam. Open-loop geothermal systems — “in which water is extracted from a well and then injected back into the same well or a second well” — are categorized as water wells, and are regulated by the state’s existing water well standards.

Learn more about participating in the GHEW standards project and join an email list at the project website:


1999 draft GHEW standards.pdf174.57 KB