Boise Will Inject Hot Water Back Underground

The capital’s historic source of winter heat could be used for more buildings as it moves into the 21st century.

City Hall, the Statehouse and Boise High School are among 43 prominent structures heated by geothermal water.

If a new 3,000-foot-deep well being drilled downtown works as officials hope, more places could be heated with the energy-saving hot water.

The water level in the geothermal aquifer is dropping as it supplies water to the heating systems. The Idaho Department of Water Resources placed a cap on the amount of hot water that can be tapped, concerned about a potential reduction in water pressure.

The city’s new $870,000 well being bored would inject the “used” water back into the aquifer in hopes of maintaining the pressure.

The water now is dumped into the Boise River. A U.S. Department of Energy grant is paying for the injection well. But experts do not know if it will work when completed in mid-May.

The city’s three existing wells pump 150 million gallons of 174-degree water a year. When discharged, the water temperature is 95 to 100 degrees.