Yes. You can use an existing water well for your geothermal system. If it has sufficient water flow and a place for water discharge.

For a vertical system, holes (approximately four inches in diameter) are drilled about 20 feet apart and 100 to 400 feet deep. Two pipes, connected at the bottom with a U-bend to form a loop, are inserted into the hole and grouted to improve performance.

Domestic Standing Column wells are typically 6 inch rock bores with 8 inch casing pocketed into the bedrock to assure segregation of surface water from pure groundwater. Well bore depths provide the design heat transfer required to satisfy the buildings dominant heating or cooling load.

Horizontal loops are less practical and can need up to 1200-1800 feet of underground space for a mid-sized home. Vertical loops dive deep into the ground, taking up much less space but needing a greater depth of installation. Vertical loops need around 3-500 feet of depth.