Permitting Geothermal Heat Pumps

Considering installing a geothermal heat pump? In Washington, geothermal heat pumps require permits. The location and design determine which permits apply. Permits for these systems are not new. However, many installers and property owners may not be aware of the requirements.

Contact the ORIA Information Center at 1-800-917-0043 or for additional questions and assistance.

Open Loop Systems - Water Right and NPDES Permits

A water right is required if a system obtains water from the ground or surface water such as a lake, pond, or stream. Depending on the system design and water availability, priority processing as a non-consumptive, beneficial use may be available. Marine waters, including Puget Sound, do not require a water right.

Heat pumps that discharge to a surface water body require a National Pollutant Discharge Elimination System (NPDES) permit from Ecology. Annual fees are based on the schedule for Individual NPDES non-contact cooling water without additives (WAC 173-224-040). For a typical residential system that discharges 10 gpm, annual fees are approximately $2,500 per year. A larger system that discharges 160 gpm requires a $10,000 annual fee. At this time, a General NPDES permit and exemptions for low volume discharges are not available.

Residential closed loop surface water systems do not require a NPDES permit at this time. However, closed loop commercial or municipal systems may require an Individual NPDES permit.

Closed Loop Ground Systems – Public Project Requirements

Public work, including publicly funded projects, must comply with the Department of Labor and Industries (LNI) prevailing wage requirements as well as Ecology's regulations for well drilling. Definitions for job types or workers (for example, well drillers) may be different under LNI and Ecology requirements.

Public projects must meet both LNI and Ecology definitions. Check with each agency to verify requirements.

Other Considerations

Workers' compensation through the Department of Labor and Industries (LNI) has specific rates for different job classifications to provide statewide no-fault insurance coverage for employers and workers. For information on what workers' compensation classifications apply to well drillers, contact LNI at (360) 902-4817. Also see

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