- What This Cheat Sheet Covers (and What It Doesn't)
- The Exam at a Glance
- Eligibility and Application Rules
- The Ten Duty Areas You Must Know
- Domain 5 Deep Dive: Constructing the Loop Well
- Test-Day Conditions and Score Report
- Scheduling Your Review Around the Domains
- Renewal Rules After You Pass
- Pay and Hiring: What to Keep Straight
- Reference Library Worth Knowing
- Frequently Asked Questions
- The exam is 75 multiple-choice questions in 90 minutes, costs USD 125, and requires at least 70% to pass.
- Eligibility requires age 20 or older plus 24 consecutive months building loop wells or conventional water-supply wells.
- Submit all application materials within 12 months of the qualifying exam, including two references from outside your current company.
- Renew annually by December 31 with seven continuing-education hours/points and a signed conduct-and-licensing affidavit.
What This Cheat Sheet Covers (and What It Doesn't)
This page is a compressed review of the Certified Vertical Closed Loop Driller credential, awarded to individuals by the National Ground Water Association (NGWA) through the Vertical Closed Loop (VCL) examination. Read it as a final-week refresher or as a map before you dig into longer material like the CVCLD study guide.
A scope note matters here. CVCLD is an independent designation. It is not the same thing as the CWD or CWD/PI drilling and pump examinations, it is not another geothermal qualification, and it is not state licensure. One examination earns the credential, and it stands apart from CWD and CWD/PI. If you are comparing paths, keep those boundaries clear so you do not study the wrong topic tables. For a plain-language definition of the credential itself, see What Is CVCLD Certification?
The Exam at a Glance
Memorize these figures. They come directly from the NGWA exam page and certification FAQ.
| Item | What to Know |
|---|---|
| Awarding body | National Ground Water Association (NGWA) |
| Test delivery | PSI proctored, computer-based testing at test centers |
| Exam | Vertical Closed Loop (VCL) examination |
| Exam fee | USD 125 |
| Format | 75 multiple-choice questions |
| Time limit | 90 minutes |
| Passing score | At least 70% |
| Retakes | No mandatory waiting period after a failed attempt |
| Score report | Provided before you leave the testing center |
| Membership | Optional |
Do the pacing math early: 90 minutes across 75 questions leaves a little over a minute per item. That is comfortable for recall questions and tight for anything that requires working through a procedure sequence in your head. For a deeper look at the cutoff, see CVCLD passing score, and for realistic expectations about difficulty, read how hard the CVCLD exam is.
A note on fees and membership
The VCL exam page publishes a single USD 125 examination fee. NGWA's general enrollment application mentions member discounts across its certification program, but no separate VCL member/nonmember price split is published, so do not assume one. Membership is optional for this credential. A full cost walkthrough lives in the CVCLD certification cost breakdown.
Eligibility and Application Rules
Eligibility has two hard requirements:
- Age: 20 or older.
- Experience: at least 24 consecutive months constructing loop wells or conventional water-supply wells.
Note the word "consecutive." Scattered seasonal work that does not add up to an unbroken 24-month stretch is not what the requirement describes. The full eligibility discussion is in CVCLD requirements.
The application package
You must submit all required application materials within 12 months of the qualifying exam. The package includes:
- The certification agreement.
- A legal-compliance affidavit.
- Two groundwater-industry professional references who are outside your current company and can verify the required experience.
The reference rule trips people up. A boss or coworker at your current employer does not satisfy it, however well they know your work. Line up two outside references early, because chasing signatures late can eat into your 12-month window.
The Ten Duty Areas You Must Know
The ten domains below reproduce duties A through J from NGWA's DACUM Research Chart for Geothermal Contractors (June 2017), currently linked as the Geothermal Vertical Closed Loop Drilling Operations DACUM. NGWA expressly recommends this document for exam preparation.
Important caveat: these are unweighted job-task competencies. They are not a verified percentage blueprint, and you should not assume that a domain with many subtasks carries proportionally many exam questions. Study all ten. For a fuller treatment, see the CVCLD exam domains guide.
| # | Domain | Think of it as... |
|---|---|---|
| 1 | Assess Client Needs | What the customer needs before any rig turns |
| 2 | Develop Project Plan | Turning needs into a workable plan |
| 3 | Initiate Project Plan | Getting the plan moving |
| 4 | Mobilize for the Site | Getting equipment and crew to the job |
| 5 | Construct Closed Loop Well | The core drilling and installation work |
| 6 | Decommission Wells | Properly closing wells out of service |
| 7 | Demobilize the Site | Leaving the site correctly |
| 8 | Close Out Project | Finishing the job's paperwork and handoff |
| 9 | Manage Business Activities | The business side of running drilling work |
| 10 | Pursue Professional Development | Staying current in the trade |
Reading the list as a project lifecycle
The domains run in the order a job unfolds: assess, plan, initiate, mobilize, construct, decommission where relevant, demobilize, close out. Domains 9 and 10 sit alongside that arc as ongoing responsibilities. If a question describes a situation, ask yourself where in the lifecycle it falls. That framing often narrows four answer choices to one.
Domains 1-3: Front-End Work
Candidates should be able to reason about what happens before mobilization, since mistakes here cascade into the field.
- Distinguish client-needs discovery from detailed planning.
- Recognize that initiating a plan is a distinct step from developing it.
- Expect scenario questions where the right answer is the next appropriate step, not the final one.
Domains 6-8: Back-End Work
Decommissioning, demobilizing and closing out are easy to under-study because they feel routine.
- Treat decommissioning wells as its own competency, not an afterthought to construction.
- Know the difference between leaving the site (demobilize) and finishing the project's administrative loop (close out).
Domains 9-10: The Professional Layer
Managing business activities and pursuing professional development round out the list.
- Expect questions about operating as a responsible contractor, not just a driller.
- Professional development ties directly to the continuing-education duty you take on after certification.
Domain 5 Deep Dive: Constructing the Loop Well
Construct Closed Loop Well is the technical heart of the credential, and it is where your hands-on experience should earn its keep. Per NGWA's task analysis, this duty includes:
- Pressure testing before and after installation.
- Loop flow testing.
- Tremie grouting.
- Displaced-fluid handling.
- Grout-subsidence and top-off checks.
Key Takeaway
Know the sequence, not just the vocabulary. Pressure testing happens both before and after installation, and grout settling means a follow-up check and top-off. Questions in this area tend to reward understanding of why each step exists and when it occurs.
Memory hooks for the construction sequence
- Test, install, test again: pressure testing brackets installation.
- Grout goes in through the tremie: tremie grouting is the placement method to associate with sealing the annulus.
- Displacement creates a handling duty: when grout or other material pushes fluid out, that displaced fluid must be managed.
- Grout settles: plan to check for subsidence and top off.
- Flow testing confirms the loop works: it is a distinct check from pressure testing.
Treat these as a checklist you can run mentally on any scenario question. If a question describes a loop that has just been grouted, ask what check comes next and what could have changed since placement.
Test-Day Conditions and Score Report
The currently linked NGWA Exam Preparation Success Guide (May 2019) sets the ground rules for the testing room:
- The exam is closed-book.
- Bring government-issued identification.
- No outside materials are permitted.
Testing runs through PSI test centers, and registration goes through the NGWA page on the PSI test-taker site. Arrive with matching identification and leave your reference materials at home. You will receive a score report before leaving the testing center, so there is no anxious wait for results.
One more honest caveat from the source material: the general Exam Preparation Success Guide notes that VCL source citation is still in development. Its water-well and pump topic tables are separate and should not be transplanted into your VCL preparation.
Scheduling Your Review Around the Domains
If you have about four weeks, sequence your review so the highest-stakes technical material gets repeated exposure. This is one possible arrangement, not an official plan.
Domain 5 First
- Walk through pressure testing, flow testing, tremie grouting, displaced-fluid handling and subsidence checks.
- Do this early because it is the densest technical content and benefits from repetition.
Domains 1-4
- Cover client needs, project planning, initiation and mobilization as one connected front-end sequence.
Domains 6-8
- Review decommissioning, demobilization and close-out, which are the domains most often skimmed.
Domains 9-10 and Full Review
- Cover business management and professional development, then take timed 75-question practice sets at 90 minutes.
Because the domains are unweighted, do not skip the ones that feel less technical. You can drill timed question sets on the CVCLD practice test site, and the CVCLD training overview helps you decide how to fill experience gaps.
Renewal Rules After You Pass
The credential is not permanent. Renewal is annual, with a hard deadline of December 31 each year.
| Renewal Element | Requirement |
|---|---|
| Frequency | Annually |
| Deadline | December 31 |
| Continuing education | Seven hours/points |
| Affidavit | Signed, addressing professional conduct and required operating licenses |
| Ongoing standard | Maintain a high standard of work |
| Renewal fee | Required; the current amount was not verified, so confirm it with NGWA |
The first annual renewal and education-reporting period is the first full calendar year after your initial certification. That means if you certify partway through a year, your first full reporting period begins the following January. Check NGWA's maintaining-your-certification page for the current fee before you budget. The long-term value of keeping the credential is examined in whether CVCLD certification is worth it.
Pay and Hiring: What to Keep Straight
No credential-specific CVCLD pay figure is published, so beware of any source that quotes one confidently. When researching earnings, keep two distinctions in mind:
- Shallow ground-source heat-pump loop drilling (the vertical closed loop world this credential belongs to) is a different line of work from deep geothermal-power drilling. Do not mix their pay data.
- The closest occupational proxy is Earth Drillers, Except Oil and Gas, tracked by O*NET. That is a broad occupation, not CVCLD-only pay.
Employers that tend to value the credential are those doing loop-field drilling for ground-source heat-pump systems, along with water-well contractors who add geothermal loop work. For a careful discussion, see the CVCLD salary guide, and for the job side, CVCLD jobs.
Reference Library Worth Knowing
NGWA's official recommended references include:
- Guidelines for the Construction of Loop Wells for Vertical Closed Loop Ground Source Heat Pump Systems
- Lexicon of Groundwater and Water Well System Terms
- Groundwater & Wells, third edition
The contents of these paid publications were not retrieved for this cheat sheet, so treat them as pointers to what NGWA considers authoritative rather than as sources summarized here. The loop-well guidelines are the most obviously aligned with Domain 5. The lexicon is a sensible companion if terminology is your weak point, since exam questions assume you speak the trade's vocabulary fluently.
Frequently Asked Questions
The Vertical Closed Loop examination has 75 multiple-choice questions with a 90-minute time limit. It is delivered by PSI as proctored, computer-based testing at a test center.
NGWA's certification FAQ specifies a passing score of at least 70%. You receive a score report before leaving the testing center.
Yes. NGWA specifies no mandatory waiting period for retakes after a failed exam. Each attempt carries the USD 125 examination fee, so review your weak domains first.
No weights are verified. The ten domains reproduce duties A-J from NGWA's 2017 DACUM chart as unweighted job-task competencies recommended for preparation, not an official percentage blueprint. Study all ten.
Renew by December 31 each year with the renewal fee, seven continuing-education hours/points and a signed affidavit covering professional conduct and required operating licenses. The current fee amount should be confirmed directly with NGWA.