Geothermal permit requirements in California for a home heat pump are set close to home. The state writes minimum well standards, and a local agency issues the permit for the drilled ground loop. This page covers home ground source heat pumps, checked on October 12, 2026. It doesn't cover geothermal power plants.
Do You Need a Permit for a Home Geothermal System in California?
Yes, for a drilled ground loop. As of October 12, 2026, California law counts a ground source heat pump well as a geothermal heat exchange well, and local agencies issue the permits for well construction.
A geothermal heat exchange well is the hole that holds the buried loop of a ground source heat pump. The Water Code defines it in section 13713 as an uncased excavation that uses the earth to heat and cool, where the ground is 30 degrees Celsius (86 degrees Fahrenheit) or cooler. The loop must be closed, so its fluid can't escape into the ground.
The Department of Water Resources (DWR) says on its wells page that well owners need a permit from the local environmental health agency or local water district before construction starts.
Who Issues a Geothermal Heat Exchange Well Permit?
A local enforcing agency issues it, often the county environmental health department. In some places a city or a water district does the job.
DWR's well standards page says these local agencies issue the permits, enforce the local well ordinance and carry out inspections. DWR lists the local agencies by county on its permitting agencies page.
| Step | Who does it | What happens |
|---|---|---|
| Minimum standards | DWR | Publishes the statewide well standards, Bulletin 74, which cover geothermal heat exchange wells |
| Local rules | County, city or water district | Adopts a local well ordinance at least as strict as the state standards |
| Permit | Local enforcing agency | Issues the permit for well construction |
| Inspection | Local enforcing agency | May inspect during and after construction |
| Report | Well driller | Sends a well completion report to DWR |
Why Do Geothermal Permit Rules Differ From County to County?
The state standards are a minimum. Counties, cities and water districts can adopt well ordinances that meet or exceed them, so the requirements change from place to place.
That is how DWR's well standards page, linked above, explains it. DWR also says there that the standards were last updated in 1991 and that an update is under way. Its list of publications shows the geothermal heat exchange well standards as a draft dated April 1999.
Until DWR's recommended standards for these wells are in place, Water Code section 13800.5 lets a local agency adopt temporary rules of its own. So the local agency is the place to ask what applies at a given address.
Who Is Allowed to Drill a Geothermal Heat Exchange Well?
The person responsible for the drilling must hold a C-57 Water Well Contractor's License. Water Code section 13750.5 applies that rule to geothermal heat exchange wells.
The rule in section 13750.5 covers digging, boring and drilling the well, and also deepening it or destroying it. DWR's wells page, linked above, says the Contractors State License Board issues the C-57 license.
What Has to Be Filed After the Well Is Drilled?
The driller files a well completion report with DWR within 60 days of finishing the work. Water Code section 13751 sets that deadline.
DWR's well completion reports page repeats the 60-day rule and says drillers file online, through an account tied to their C-57 license. For a geothermal heat exchange well, section 13751 says the report must include:
- A description of the site, exact enough to find it, and the number of geothermal heat exchange wells drilled on the lot
- The borehole diameter and depth, and the type of system installed
- The methods and materials used to seal off surface water or contaminated water
- The methods used to keep contaminated water in one aquifer from mixing with water in another
- The driller's signature
What Should a Homeowner Check Before the Drilling Starts?
Three things: which local agency issues the permit, whether the driller holds a C-57 license, and who will file the well completion report.
- Find the local enforcing agency for the address on DWR's permitting agencies page, linked above, and ask what it requires for a geothermal heat exchange well.
- Ask the driller for the C-57 license number.
- Ask for a copy of the permit before work starts and a copy of the well completion report afterwards.
Then check what help is on offer. The eligibility check and the rebate calculator show the verified programs for a specific address.
Frequently Asked Questions
Does a horizontal ground loop need a well permit?
The Water Code definition covers an uncased excavation made by any method. Whether a trenched loop needs a permit at a given address is a question for the local enforcing agency.
Does DWR issue geothermal permits?
No. DWR writes the minimum well standards and keeps the well completion reports. Local enforcing agencies issue the permits.
Did the federal tax credit for geothermal heat pumps end?
Yes. The federal 25D credit ended for systems completed after December 31, 2025.
The guide to the federal home energy credits that ended has the details.
Planning a geothermal system? See the verified rebates for your address with the free rebate calculator.