Land Development Services

Fairfax County, Virginia

CONTACT INFORMATION: Regular hours for calls and emails are 8 a.m. – 4 p.m., Monday through Thursday, and 9:15 a.m. - 4 p.m. on Friday.

TTY 711

12055 Government Center Pkwy
Fairfax, VA 22035

Bill Hicks,

Geothermal HVAC Systems

Geothermal HVAC Systems

This information is the most common for how to obtain the necessary permits for a residential geothermal HVAC system and is not representative of all the conditions you may encounter.


To install a geothermal heating and air conditioning system, you will be required to obtain a mechanical permit, plumbing permit (for any gas piping) and electrical permit (for electrical work)from Land Development Services and well permit from the Health Department. Related fees vary depending on the full scope of your project; use the online fee estimator to help determine costs. A $500 fee is charged by the Health Department for well permits.


There are three major types of geothermal HVAC systems used in residential properties.

  • The Horizontal Loop System which requires digging long trenches below the frost line to lay system piping.
  • The Horizontal Bored System which utilizes directional boring to drill the system piping underground with little to no land disturbance.
  • The Vertical Well System which requires looped patterned wells drilled several hundred feet deep. This is the predominant system seen in Fairfax County.

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  • Well Permit form. A completed Onsite Sewage System and Well Permit Application and a drawing locating wells on the property is required to be emailed to the Health Department to initiate permit application. A layout inspection by Health Department staff may be required prior to permit issuance. To learn more email or call 703-246-2201, TTY 711. The well permit must be issued prior to apply for the mechanical permit.
  • Mechanical, plumbing or electrical permits. When applying for a residential mechanical, plumbing or electrical permit for the wells or loops, no plans are required. However, installation of the interior HVAC equipment and related duct work, requires the submission of the Residential HVAC Certification with permit application. You must apply for these permits online; to learn more, contact the Permit Application Center via email or at 703-222-0801, TTY 711.
  • Site-related plan. For geothermal  systems that disturb no more than 2,500 sq. ft. of earth during installation, you will be required to upload a house location plat for review with your mechanical permit application through ProjectDox, the county’s eplan platform. For systems that disturb more than 2,500 sq. ft., you will be required to submit a conservation or grading plan also through ProjectDox. Please review our Site-Related Plans publication for more information.
  • Permit-related forms. Most required permit data is captured during the online permit application process. However, there may be instance when an additional form may be required to be upload at permit application. When property ownership must be verified, a Property Ownership Affidavit will be required. When there is no contractor and the applicant is not the property owner, a Permit Authorization Affidavit is required.
  • Inspection form. A Geothermal Certification is required to be submitted to inspections staff prior to final inspection of the mechanical permit of the well or loops.
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