- What the Ten Domains Actually Represent
- Exam Format and Registration Mechanics
- Domains 1-3: Client Needs and Planning
- Domains 4-5: Mobilization and Constructing the Loop Well
- Domains 6-8: Decommissioning, Demobilization and Close-Out
- Domains 9-10: Business and Professional Development
- Sequencing Your Preparation by Domain
- Eligibility, Application and Renewal
- Frequently Asked Questions
- The ten domains are NGWA's DACUM duties A-J for geothermal contractors, not an officially weighted exam blueprint.
- The VCL exam has 75 multiple-choice questions, a 90-minute limit, a USD125 fee and a 70% minimum passing score.
- Construct Closed Loop Well is the most technical domain: pressure testing, flow testing, tremie grouting and grout top-off checks.
- Eligibility needs age 20+ and 24 consecutive months constructing loop wells or conventional water-supply wells.
What the Ten Domains Actually Represent
If you are building a study plan for the Certified Vertical Closed Loop Driller (CVCLD) credential, the first thing to understand is where the "ten content areas" come from. They reproduce duties A through J in the National Ground Water Association's DACUM Research Chart for Geothermal Contractors (June 2017), currently linked as the Geothermal Vertical Closed Loop Drilling Operations DACUM. A DACUM chart is a job-task analysis: working professionals describe what the job consists of, and the result is organized into duties and tasks.
That framing matters because many candidates arrive expecting a published weighting table, the way some credentials list "Domain 3: 22%." NGWA does not publish one for the VCL examination, so any site that gives you exact percentages is guessing. For a deeper discussion of how to approach that uncertainty, see our CVCLD study guide, and for the overall structure of the credential, our overview of what CVCLD certification is.
The ten domains at a glance
| Domain | Name | Where it sits in a project |
|---|---|---|
| 1 | Assess Client Needs | Before any contract exists |
| 2 | Develop Project Plan | Design and estimating |
| 3 | Initiate Project Plan | Approvals and kickoff |
| 4 | Mobilize for the Site | Getting people and equipment on location |
| 5 | Construct Closed Loop Well | The drilling, installation and grouting work |
| 6 | Decommission Wells | Sealing and abandoning wells |
| 7 | Demobilize the Site | Leaving the site in proper condition |
| 8 | Close Out Project | Documentation and handoff |
| 9 | Manage Business Activities | Company-level operations |
| 10 | Pursue Professional Development | Ongoing learning and credential upkeep |
Exam Format and Registration Mechanics
The CVCLD is earned through a single examination, the Vertical Closed Loop (VCL) exam. It is independent of the CWD and CWD/PI drilling and pump examinations, so you do not need to hold or sit those to pursue this designation. NGWA awards the individual credential, and PSI delivers proctored computer-based testing at test centers.
| Item | What NGWA publishes |
|---|---|
| Question count | 75 multiple-choice questions |
| Time limit | 90 minutes |
| Exam fee | USD125 for the VCL examination |
| Passing score | At least 70% |
| Retakes | No mandatory waiting period after a failed attempt |
| Score report | Provided before you leave the testing center |
| Testing conditions | Closed-book, government-issued identification, no outside materials |
| Membership | Optional |
Ninety minutes for 75 questions works out to roughly 72 seconds per question. That is comfortable for recall items and tight for anything that asks you to work through a calculation or a sequence of steps, which is why you should practice the arithmetic-heavy topics under a clock. Our passing score breakdown explains how a 70% threshold translates into the number of questions you can miss on a 75-question test, and the certification cost guide covers the full fee picture, including what is and is not verified about renewal pricing.
The preparation and testing conditions come from NGWA's Exam Preparation Success Guide (May 2019). One caution: that guide states that source citation for the VCL exam is still in development, and its water-well and pump topic tables belong to other examinations. Do not transplant those topic lists into your CVCLD plan. For scheduling logistics, see the exam dates and scheduling guide.
Domains 1-3: Client Needs and Planning
The first three domains cover everything that happens before a drill rig turns. Candidates who work primarily as rig operators sometimes underestimate these because the field crew rarely owns them, but a certified driller is expected to understand how decisions made upstream shape the borehole.
Domain 1: Assess Client Needs
This is the front end of the job: understanding what the customer is trying to achieve and what constraints the site imposes.
- Gathering information about the heating and cooling load the loop field must serve
- Recognizing site conditions that affect feasibility, such as access, geology and available space
- Communicating realistic expectations about what a vertical loop installation involves
Domain 2: Develop Project Plan
Once needs are understood, the plan turns them into a buildable scope.
- Translating load and site information into a loop field design basis
- Estimating materials, equipment, labor and schedule
- Identifying regulatory and permitting requirements that apply to loop wells in the project's jurisdiction
Domain 3: Initiate Project Plan
Initiation is where the plan becomes a commitment: agreements, approvals and the setup that precedes mobilization.
- Securing the permits and approvals the plan identified
- Confirming scope, responsibilities and communication channels with the client and other trades
- Coordinating utility locates and site readiness before equipment arrives
Expect scenario-style questions here: given a described situation, what should happen first, what is the responsible next step, or which consideration was overlooked. The correct answer is usually the one that reflects sound professional practice and legal compliance rather than the fastest route to starting work.
Domains 4-5: Mobilization and Constructing the Loop Well
Domain 4: Mobilize for the Site
Mobilization covers getting the right equipment, materials, people and safeguards onto the site and ready to drill. The practical themes are site safety setup, protecting the property and nearby infrastructure, staging materials such as loop pipe and grout, and making sure the crew understands the plan before work begins. Questions in this area reward field common sense, but they also reward knowing the formal safety and protection expectations that apply to drilling operations.
Domain 5: Construct Closed Loop Well
This is the heart of the credential and the domain where a candidate's hands-on experience is most directly tested. NGWA's materials for this duty include pressure testing before and after installation, loop flow testing, tremie grouting, displaced-fluid handling and grout-subsidence or top-off checks. Together they follow the life of a loop well from the open borehole to a sealed, verified installation.
Domain 5 topics worth mastering
Think of construction as a chain: each step protects the integrity of the next, and the exam tends to probe the reasoning behind the order.
- Pressure testing before and after installation: why the loop assembly is tested before it goes down the hole, why it is tested again once installed, and what a pressure loss indicates
- Loop flow testing: confirming that fluid circulates through the loop as expected so that obstructions or kinks are caught before the well is finished
- Tremie grouting: placing grout from the bottom of the borehole upward through a tremie pipe so the annulus is filled without voids and the loop is thermally and hydraulically sealed
- Displaced-fluid handling: managing the drilling fluid and water pushed out of the borehole as the loop and grout go in, in a way that protects the site and the environment
- Grout subsidence and top-off checks: recognizing that grout can settle after placement and that the annulus must be verified and topped off so the seal is complete
NGWA lists Guidelines for the Construction of Loop Wells for Vertical Closed Loop Ground Source Heat Pump Systems among its recommended references, and that document is the natural companion to this domain. Paid reference contents were not retrieved for this article, so use the official reference itself for specifics such as grout properties and procedural detail rather than relying on a summary. For a sense of how demanding this material is relative to your experience, read our difficulty guide.
Domains 6-8: Decommissioning, Demobilization and Close-Out
Domain 6: Decommission Wells
Not every borehole ends up as a working loop. Failed or abandoned wells, and wells at the end of their service life, must be sealed so they do not become pathways for contamination between formations or from the surface.
- Recognizing when a well must be decommissioned rather than left in place
- Understanding that sealing is a regulated activity with documentation expectations
- Protecting groundwater as the guiding principle behind every decommissioning decision
Domain 7: Demobilize the Site
Leaving a site is part of the job, not an afterthought.
- Managing cuttings, fluids and waste in accordance with applicable requirements
- Restoring the site and confirming that wells are properly finished and protected
- Removing equipment and materials while leaving the property safe
Domain 8: Close Out Project
Close-out turns completed field work into a documented, handed-off project.
- Assembling records of what was installed and where, including testing results
- Meeting reporting obligations tied to well construction
- Transferring information to the client and closing the commercial side of the job
Candidates who learned the trade on the job often know how decommissioning and demobilization are done locally but are less sure of the reasons behind the requirements. The exam favors reasons. If you can explain why a well is sealed the way it is and why records are kept, you will handle unfamiliar phrasings far better than someone relying on shop habits. Our cheat sheet is useful for a last-pass review of these procedural facts.
Domains 9-10: Business and Professional Development
Domain 9: Manage Business Activities
A certified driller is often an owner, foreman or lead, and the company-level side of the work is part of the competency set.
- Maintaining the licenses, insurance and legal compliance the business depends on
- Managing personnel, equipment and safety programs
- Keeping the financial and recordkeeping side of the operation sound
Domain 10: Pursue Professional Development
This domain mirrors the credential's own philosophy. Certification is not a one-time event, and the renewal requirements make that concrete.
- Staying current with evolving standards, techniques and regulations
- Participating in continuing education and industry activity
- Maintaining a high standard of work and professional conduct
These two domains are the ones candidates most often skim, because they feel less technical. Resist that instinct. Questions drawn from them tend to be among the more approachable items on the exam, and missing easy points here makes the 70% threshold harder to reach.
Sequencing Your Preparation by Domain
Because the domains are unweighted, the sensible approach is to allocate time by your own weakness rather than by an invented percentage. A field-heavy candidate should front-load planning, business and close-out material; an office-based candidate should front-load Domain 5. The sample sequence below assumes a six-week window and pairs each stretch with a reason.
Domains 1-4 and 9-10
- Read the DACUM chart itself so you see every task listed under each duty
- Cover the planning and business domains first, since they are the most likely gaps for hands-on drillers
Domain 5 in depth
- Work through the loop well construction guidelines step by step
- Drill pressure testing, flow testing, tremie grouting, displaced fluids and grout top-off until you can explain the reasoning for each
Domains 6-8
- Review decommissioning, demobilization and close-out with attention to why each requirement exists
Timed practice
- Take full-length sets of 75 questions in 90 minutes under closed-book conditions
- Revisit every domain where you scored below your target
Timed practice is where our CVCLD practice tests fit best, because they let you rehearse the 75-question, 90-minute format before you sit for the real thing. When you want to gauge your readiness, our practice test platform can show you which domains are costing you points.
Eligibility, Application and Renewal
Knowing the domains is only part of the path. To qualify, you must be at least 20 years old and have at least 24 consecutive months of experience constructing loop wells or conventional water-supply wells. The full list of prerequisites is in our requirements guide.
Your application materials must be submitted within 12 months of the qualifying exam. They include the certification agreement, a legal-compliance affidavit, and two groundwater-industry professional references from outside your current company who can verify the required experience. Line up those references early, since they depend on other people's schedules.
Keeping the credential current
- Renew annually by December 31
- Submit the renewal fee, seven continuing-education hours or points, and a signed affidavit covering professional conduct and required operating licenses
- The first annual renewal and education-reporting period is the first full calendar year after initial certification
A current renewal-fee amount was not verified for this article, so confirm it on NGWA's page on maintaining your CVCLD certification before budgeting. Weighing the total commitment against the career benefit is the subject of our worth-it analysis, and the compensation picture is covered in the salary guide.
Frequently Asked Questions
NGWA has not published a verified percentage weighting for the VCL examination. The ten domains reproduce duties A-J from its DACUM job-task chart and are recommended for exam preparation, but they are unweighted competencies, so avoid any source that claims exact percentages.
The Vertical Closed Loop examination has 75 multiple-choice questions with a 90-minute limit. The fee published for the VCL examination is USD125, and the passing score is at least 70%.
Because the domains are not officially weighted, base your allocation on your own gaps. Construct Closed Loop Well is the most technical domain, covering pressure testing, loop flow testing, tremie grouting, displaced-fluid handling and grout top-off checks, so it deserves deep review for most candidates.
NGWA's certification FAQ states there is no mandatory waiting period for failed-exam retakes. You also receive a score report before leaving the testing center, which helps you identify which areas to review.
No. The CVCLD requires one examination, the VCL exam, and is independent of the CWD and CWD/PI drilling and pump examinations.
For a broader introduction to the credential, start with what CVCLD is, and when you are ready to test your knowledge across all ten domains, head to our practice test site.