Geothermal Engineer: Job, Salary, and How to Become One

"Geothermal engineer" is a job title that people hold and employers advertise, and it is not an occupation in the federal government's own occupational database. Search O*NET, the US Department of Labor's occupational taxonomy, for "geothermal" and eleven occupations come back. Only two carry the word in their title: Geothermal Production Managers and Geothermal Technicians. Neither is an engineer. The work gets classified instead under occupations like Mechanical Engineers, Geoscientists and Earth Drillers — some of them engineering codes, some not — held by people who happen to work on geothermal.

That has practical consequences. No federal wage series is published under the title, which is why salary figures for "geothermal engineer" vary so widely from one site to the next. Job listings for similar work carry a range of titles, since each employer files the role under a discipline it already hires for. And NCEES, which writes the Professional Engineer exams, offers no geothermal-specific PE exam: its exam-registration selector lists 25 disciplines and geothermal is not among them.

The title also covers two different jobs. One is the subsurface and power-plant side: reservoirs, wells, drilling, turbines. The other is the ground-source heat pump side: loop design and building HVAC. They differ in employer, credential, daily work and the pay comparison that makes sense, so the two are kept apart throughout what follows.

Two Jobs Wearing One Title

When a listing says "geothermal engineer", the first question is which field it belongs to. The answer changes what degree, license or certification matters, and what the pay comparison should be.

The subsurface and power-plant side

This is geothermal as an energy source: finding hot rock, drilling into it, bringing fluid to the surface and running it through a plant that makes electricity. The O*NET occupations that describe this work are Geothermal Production Managers, Geoscientists, Earth Drillers and Mechanical Engineers. The manager code is defined around the plant:

Manage operations at geothermal power generation facilities. Maintain and monitor geothermal plant equipment for efficient and safe plant operations.

O*NET, 11-3051.02 Geothermal Production Managers (Updated 2025)

The sample job titles O*NET reports for that code are "Plant Manager, Plant Supervisor, Power Plant Operations Manager". Nobody in that list is called an engineer. Our guides to geothermal drilling and wells and how geothermal power plants work cover the technical side of these jobs, and our explainer on enhanced geothermal systems covers where the subsurface work is heading.

The ground-source heat pump side

This is geothermal as a way to heat and cool a building: a loop of pipe in the ground, a heat pump inside, and a design job that sizes both to the building's loads. Of the eleven occupations the geothermal search returns, the ones on this side are Mechanical Engineers, Geothermal Technicians, Plumbers, Pipefitters and Steamfitters, and Sheet Metal Workers. One more occupation is worth reading alongside them even though the geothermal search does not return it, because its definition is built around buildings rather than plants — O*NET's Energy Engineers, Except Wind and Solar:

Design, develop, or evaluate energy-related projects or programs to reduce energy costs or improve energy efficiency during the designing, building, or remodeling stages of construction. May specialize in electrical systems; heating, ventilation, and air-conditioning (HVAC) systems; green buildings; lighting; air quality; or energy procurement.

O*NET, 17-2199.03 Energy Engineers, Except Wind and Solar (Updated 2026)

On this side there is a system-design certification track from IGSHPA that speaks to the work directly, covered below, alongside whatever state engineering licensure a given role calls for. If you are coming at it from an HVAC business rather than a degree, adding geothermal to an HVAC business is the contractor route in, and our geothermal loop design guide shows what the design work actually involves.

The tell in a job listing

Look for the employer and the object. A utility, power developer or drilling contractor advertising work on wells, reservoirs or a plant is the subsurface side. An engineering consultancy, mechanical contractor or building owner advertising loop fields, heat pumps or HVAC is the heat-pump side. Mechanical engineering reads onto both sides, because its O*NET definition spans "engines, machines" and "centralized heat, gas, water, and steam systems" — that division into two sides is this article's, not O*NET's.

What the Federal Database Actually Lists

O*NET is the Department of Labor's occupational database and the source for every occupation and wage figure on this page. A keyword search for "geothermal" returns these eleven occupations, in the order the results table lists them:

O*NET's occupational taxonomy contains no occupation titled geothermal engineer. That is not the same as saying the job does not exist. People hold the title and get paid under it. What the title does not have is a code of its own, so the things published per occupation — a wage series, an employment count, a growth projection — are not published under it. The people doing the work are counted, but under the broader occupations they are classified into.

The Geothermal Technicians code is worth reading in full, because it does something unusual:

Perform technical activities at power plants or individual installations necessary for the generation of power from geothermal energy sources. Monitor and control operating activities at geothermal power generation facilities and perform maintenance and repairs as necessary. Install, test, and maintain residential and commercial geothermal heat pumps.

O*NET, 49-9099.01 Geothermal Technicians (Updated 2025)

One code covers both a power-plant technician and a residential heat-pump installer, which can be very different jobs. Keep that in mind when you see a "geothermal technician" wage quoted: the code does not distinguish between them, and as the next section shows, the wage printed on that page is labeled as the median for a much broader occupation.

What a Geothermal Engineer Earns

The closest defensible pay comparisons come from two places: parent-bucket numbers and whole-profession numbers. O*NET handles specializations without their own wage series by printing the parent occupation's wages and saying so in a line on the page. Three of the five occupations below carry that line. Read it before you use the number.

The three parent-bucket numbers

The $49,230 on the Geothermal Technicians page is the median for "Installation, Maintenance, and Repair Workers, All Other", the residual bucket for every unclassified repair trade. It is not a geothermal technician wage. The $126,060 on the Geothermal Production Managers page is the median for "Industrial Production Managers", people who run production at any kind of plant. The $122,930 on the Energy Engineers page is the median for "Engineers, All Other", the bucket for every engineer whose discipline has no code of its own. That last one is the figure most likely to be lifted and presented as a "geothermal engineer salary". Its label says what it is: a median across every engineering discipline that has no code of its own, geothermal or otherwise.

The two whole-profession numbers

Mechanical Engineers ($104,110) and Geoscientists ($101,920) each have their own O*NET code and wage series, so these are real medians for real professions. The catch is scope. Mechanical engineering covers everything from engine design to steam systems; geoscience covers oil, gas, minerals, groundwater and waste disposal. Each median describes that whole profession, not the geothermal work inside it.

If you want one defensible anchor for the engineering side of this career, those two are it, with the caveat that they describe the discipline, not the geothermal work within it. Do not average the five figures, and do not present any of them as a geothermal wage. The cited sources publish no geothermal-specific salary. So a page offering a single "geothermal engineer" number without saying which occupation and year it comes from has given you something the federal data does not validate — ask which code it is before you use it.

Job Outlook: Growth and Openings

O*NET publishes a projected growth band and projected job openings for 2024–2034 on each occupation page. The figures for the parent-bucket codes carry the same caveat as their wages.

Mechanical Engineers is the only occupation in this set projected to grow "much faster than average", and it carries O*NET's "Bright Outlook" flag on the search results page. Geoscientists sits in the "Average" band with a much smaller opening count. The three parent-bucket codes all sit in the slowest band and say nothing specific about geothermal demand in either direction. There is no geothermal employment count or growth rate in the federal occupational data, for the same reason there is no wage. For someone choosing a route in, that makes mechanical engineering the entry with the strongest published outlook — and the degree that keeps its value if the geothermal work in a given region does not materialize.

Geothermal Engineer Job Description

O*NET publishes no description under the title "geothermal engineer". The definitions it publishes for the occupations the geothermal search returns are the nearest federal reference available. Read against the side of the field a listing belongs to, they describe the work reasonably well.

Mechanical Engineers (both sides)

Perform engineering duties in planning and designing tools, engines, machines, and other mechanically functioning equipment. Oversee installation, operation, maintenance, and repair of equipment such as centralized heat, gas, water, and steam systems.

O*NET, 17-2141.00 Mechanical Engineers (Updated 2026)

Note what that definition does and does not cover. It names "centralized heat, gas, water, and steam systems" and the oversight of their installation, operation, maintenance and repair — language that reaches both a plant's steam side and a building's heating plant. It says nothing specific about geothermal.

Geoscientists (subsurface side)

O*NET defines the discipline as "Study the composition, structure, and other physical aspects of the Earth", with exploration "for oil, gas, minerals, or underground water" among its named uses. A geothermal reservoir job is an exploration job in these terms. The definition does not mention geothermal: it is one target among several for the same subsurface skills.

Earth Drillers (the "geothermal drilling engineer" search)

Operate a variety of drills such as rotary, churn, and pneumatic to tap subsurface water and salt deposits, to remove core samples during mineral exploration or soil testing, and to facilitate the use of explosives in mining or construction.

O*NET, 47-5023.00 Earth Drillers, Except Oil and Gas (Updated 2026)

The drilling occupation O*NET returns for "geothermal" is a skilled-trade code, not an engineering code, and its description does not use the word geothermal. Which discipline an employer files engineering oversight of a drilling program under is not something O*NET records, so expect it to vary by employer.

How to Become a Geothermal Engineer: Degree and License

NCEES offers no geothermal-specific PE exam, so the path in runs through a conventional engineering discipline. NCEES, the body that writes the Fundamentals of Engineering (FE) and Professional Engineer (PE) exams, describes the commonly accepted licensure pathway in three lines:

Generally, engineering licensing boards require P.E. candidates to have a bachelor's degree from an EAC/ABET-accredited program.

Most states require four years of acceptable, progressive, and verifiable work experience.

Licensure candidates typically must pass the FE exam and the PE exam.

NCEES, "Licensure"

The same page carries a scope caveat that applies to every sentence in this section:

These steps reflect the most commonly accepted path to licensure. Many states provide additional paths for licensure. Candidates interested in pursuing licensure are encouraged to verify the requirements in the state or territory where they plan to practice.

NCEES, "Licensure"

Which degree

NCEES says licensing boards generally require a bachelor's degree from an EAC/ABET-accredited program, and it does not name a discipline. The engineering and geoscience disciplines O*NET's geothermal search returns are mechanical engineering, geoscience and electrical engineering. Whether a dedicated geothermal engineering degree exists at a US university is covered in the gaps section below.

Which PE exam

NCEES publishes 25 PE exam disciplines. The complete list: Agricultural and Biological Engineering; Architectural; Chemical; Civil: Construction; Civil: Geotechnical; Civil: Structural; Civil: Transportation; Civil: Water Resources and Environmental; Control Systems; Electrical and Computer: Computer Engineering; Electrical and Computer: Electrical and Electronics; Electrical and Computer: Power; Environmental; Fire Protection; Industrial; Mechanical: HVAC and Refrigeration; Mechanical: Machine Design and Materials; Mechanical: Thermal and Fluids Systems; Metallurgical and Materials; Mining and Mineral Processing; Naval Architecture and Marine; Nuclear; Petroleum; Software; Structural.

Geothermal is not on it. Four entries on the list name subject matter that appears in the work described above — Mechanical: HVAC and Refrigeration, Mechanical: Thermal and Fluids Systems, Petroleum, and Civil: Geotechnical — but NCEES does not map any of them to geothermal, and which exam a given engineer should sit is not something the cited sources address. That is a question for a state board and an employer.

Why the license matters when it matters

Only a licensed engineer can prepare, sign, seal, and submit engineering drawings.

NCEES, "Licensure"

Whether any particular geothermal role legally requires a PE is a separate question, addressed in the gaps section. NCEES does establish that sealing drawings is reserved to licensed engineers, so a role that involves stamping drawings sits behind the license and a role that does not may not.

The path, in order

1. Decide which side of the field you are aiming at. It will not dictate your discipline, but it should inform the choice.
2. Complete an EAC/ABET-accredited bachelor's degree — the qualification NCEES says boards generally require. It does not have to match a geothermal "side"; check your state board's rules.
3. Pass the FE exam.
4. Accumulate the four years of "acceptable, progressive, and verifiable work experience" most states require, on geothermal projects if you can get them.
5. Pass a PE exam in one of the 25 published disciplines.
6. Verify the requirements with the licensing board of the state where you intend to practice.

The Heat-Pump Side: IGSHPA Design Certification

On the ground-source heat pump side, the credential that names the design role is not a state license but a certification from the International Ground Source Heat Pump Association (IGSHPA). IGSHPA states that it "has partnered with CSA Group on new accredited training and certification programs", and that "All of the new training is based upon the CSA/ANSI/IGSHPA C448:25 Series Design and Installation Standard for Commercial and Residential GSHP Applications."

Two design certifications are named on the IGSHPA training page. Its footnote spells them out: "GCSD = GSHP Commercial System Designer; GRSD = GSHP Residential System Designer". IGSHPA describes the commercial program this way:

designed specifically for commercial GSHP system designers and professional certification. The program addresses the gaps in traditional HVAC education by providing a learning experience that emphasizes practical application and adherence to CSA/ANSI/IGSHPA C448 Series: 25 ... and advocates for single point responsibility of all GSHP system designs.

IGSHPA, "Training & Certification"

"Single point responsibility" is the phrase to notice: a designer who owns the whole system design rather than a building-side engineer and a ground-side driller each owning half. That is the closest thing on the heat-pump side to a defined "geothermal engineer" role. It is a certification, not a license, and does not change who can seal drawings.

The page still carries transition language, and its own stated timetable has now passed, so check the current rollout status before enrolling:

Starting in 2023, IGSHPA began developing a plan for updating its entire training curriculum and certification program... The training courses and certification/certificate programs are being finalized and will be available by the end of 2025/early 2026. Some of the courses and certifications are available now.

IGSHPA, "Training & Certification"

Anyone pursuing GCSD or GRSD should check the current page rather than assume the full program is live. The page also names a separate track for "Inspectors, Code Officials, Project Managers / GSHP System Verification and Inspection", though the page does not set out what that track covers beyond its name. For the installer certifications and how the whole IGSHPA structure fits together, see our guide to becoming a certified geothermal installer.

What We Could Not Source

Each item below is a real gap, not a hedge.

• Bureau of Labor Statistics material. BLS returned HTTP 403 to every fetch on September 4, 2026: the "Careers in Geothermal Energy" page, the Occupational Outlook Handbook pages and the 2018 SOC major-groups page. That is a bot-block, not a dead page. Nothing here is sourced to BLS; O*NET is a separate Department of Labor system.
• US geothermal engineering degree programs. The Colorado School of Mines geothermal-engineering graduate page returned HTTP 403. This page makes no claim either way about whether a dedicated geothermal engineering degree exists in the United States.
• DOE workforce demand. energy.gov/eere/geothermal/geothermal-workforce-development returned HTTP 404. No DOE workforce-demand claim appears here.
• Geothermal-specific salary, headcount and growth. Stated once in the salary section and once in outlook: every number on this page is a parent-bucket or whole-profession figure, labeled as such.
• Whether a PE is legally required. The cited sources do not establish whether a PE license is required for any particular geothermal role. NCEES describes a common pathway and defers to the states.

Frequently Asked Questions