CVCLD Pass Rate 2026: What the Data Shows

What the Pass-Rate Data Actually Shows

If you searched for the Certified Vertical Closed Loop Driller pass rate hoping for a clean number like "78 percent of candidates pass," here is the straight answer: the National Ground Water Association (NGWA), which awards the credential, does not publish a pass rate in the sources reviewed for this article. The exam-specific page, the certification FAQ, the application packet, and the exam preparation guide all describe how the test works. None of them report how many candidates pass it.

That absence matters, and it is the most useful "data point" available. Any site quoting a precise CVCLD pass percentage is either inventing it, borrowing it from a different credential that happens to share the acronym, or extrapolating from something unrelated. This article will not do any of those things. Instead, it walks through what is documented about the exam, and what those documented facts imply about how difficult the test is and how you should prepare.

For a broader look at the difficulty question, see our companion piece, How Hard Is the CVCLD Exam? Complete Difficulty Guide 2026. For the score threshold itself, CVCLD Passing Score 2026: Exactly What You Need to Pass goes deeper.

Why a Single Pass-Rate Number Would Mislead You

Even if NGWA did publish an aggregate figure, it would be a weak predictor of your personal result. Three structural features of this credential make a headline percentage less meaningful than it looks.

The candidate pool is self-selected

Eligibility requires that you are at least 20 years old and have at least 24 consecutive months of experience constructing loop wells or conventional water-supply wells. People do not casually sit this exam. Everyone in the testing room has already spent two years in the field, and many were encouraged or sponsored by an employer. A pass rate from a pool like that tells you about the pool, not about how hard the questions are for someone with your specific background.

The exam tests job tasks, not trivia

The content outline NGWA recommends for preparation is a job-task analysis: its DACUM Research Chart for Geothermal Contractors (June 2017), which lists ten duties from assessing client needs through professional development. A candidate who has worked across every one of those duties will find the material familiar. A candidate who has only ever run the drill rig may find the business, planning, and decommissioning duties much less so. Pass probability therefore varies enormously by experience profile.

Retakes blur the statistics

NGWA's FAQ states there is no mandatory waiting period for failed-exam retakes. When retakes are easy, an aggregate "first-attempt" figure and an "eventually certified" figure can differ widely, and without knowing which one a source is quoting, the number is nearly useless for planning.

The Exam Mechanics That Shape Your Odds

Because pass-rate statistics are unavailable, the most defensible way to gauge difficulty is to look at the documented format. Here is what the primary NGWA sources specify for the VCL examination.

Run the arithmetic and a few things stand out. At 70%, you need roughly 53 of 75 questions correct (52.5 rounds up, so plan on 53). The 90-minute window gives you about 72 seconds per question, which is generous for a multiple-choice test but not unlimited if you tend to overthink applied scenarios. And because the exam is closed book, you cannot look up grout mix ratios, pressure-test procedures, or decommissioning requirements mid-exam. Recall has to be solid.

For the full cost picture beyond the exam fee, including renewal considerations, read CVCLD Certification Cost 2026: Complete Pricing Breakdown. A note on fees: the application materials mention member discounts across NGWA's certification program in general, but the VCL page publishes a single USD 125 price, so do not assume a separate member/nonmember split for this exam.

The Experience Requirement as a Built-In Filter

The single most important factor in your odds is not a study technique. It is whether your field experience maps onto what the exam asks. The eligibility rule requires 24 consecutive months constructing loop wells or conventional water-supply wells, and your two professional references must come from outside your current company and be able to verify that experience.

That requirement does quiet work on the pass rate. It means the exam can assume baseline competence in drilling operations and focus on whether you can apply it correctly, safely, and in compliance with industry practice. If you are still sorting out whether you qualify, CVCLD Requirements 2026: Eligibility, Prerequisites & How to Qualify lays out the application mechanics, including the 12-month window: all required application materials, including the certification agreement and legal-compliance affidavit, must be submitted within 12 months of the qualifying exam.

Where Prepared Candidates Still Lose Points

The ten duties in NGWA's DACUM chart are unweighted job-task competencies. They are expressly recommended for exam preparation, but they are not an official percentage blueprint, and you should not assume any domain carries a fixed share of the 75 questions. With that caveat, here is where experienced drillers most often have uneven preparation, based on how the duties are structured.

For a breakdown of every duty with the specific competencies behind it, see CVCLD Exam Domains 2026: Complete Guide to All 10 Content Areas. The remaining domains, Initiate Project Plan, Mobilize for the Site, and Demobilize the Site, cover the sequence of getting equipment and crews onto and off a job site correctly.

Retakes, Cost, and the Real Price of Failing

One reason pass-rate anxiety is somewhat overblown for this credential: the downside of a failed attempt is bounded. NGWA's FAQ specifies no mandatory waiting period before a retake, and you get a score report before you leave the testing center, so you learn your result immediately rather than waiting weeks.

That said, a failed attempt is not free. The published exam fee is USD 125 per sitting, and you still have to schedule a new appointment through PSI. A more important cost is psychological and practical: a failed attempt costs you the cushion of time within your 12-month application window if you let it drag on. Treat the first attempt as the one that counts.

Once certified, you will renew annually by December 31, with seven continuing-education hours or points, a signed affidavit, and the renewal fee. A current renewal-fee amount was not verified for this article, so confirm it directly with NGWA. Whether the whole investment pays off is covered in Is the CVCLD Certification Worth It? Complete ROI Analysis 2026.

A Domain-Ordered Readiness Plan

Rather than a generic study calendar, sequence your preparation by how well each duty matches your day-to-day experience. Spend the earliest weeks on the duties where you are weakest, because those are where the points are lost, and save your strongest domain for last-mile review.

For a fuller walkthrough of resources and pacing, see CVCLD Study Guide 2026: How to Pass on Your First Attempt. NGWA also lists Groundwater & Wells (third edition) and the Lexicon of Groundwater and Water Well System Terms among its recommended references. The Lexicon is worth skimming because exam questions can hinge on precise terminology. A quick final review aid is CVCLD Cheat Sheet 2026: One-Page Review of Must-Know Facts.

One caution on source material: NGWA's general Exam Preparation Success Guide (May 2019) states that source citations for the VCL exam were still in development, and its topic tables for the water-well and pump exams belong to different examinations. Use that guide for testing conditions and logistics, not as a VCL content outline. Practice questions that mirror the closed-book, multiple-choice format are available on the main practice test site.

How to Evaluate Pass-Rate Claims You See Online

Because the real figure is unpublished in the sources reviewed, you will almost certainly encounter confident-sounding numbers elsewhere. Use this quick filter before you trust any of them.

1. Check the credential. Does the source say Certified Vertical Closed Loop Driller, awarded by NGWA? Other credentials share the CVCLD acronym, and their statistics do not transfer.
2. Check for a citation. A real pass rate would come with a date, a sample size, and an issuing body. A bare percentage with no source is a red flag.
3. Ask which attempt it measures. First-attempt, all-attempt, and eventual-certification figures differ, and many sources never say which one they mean.
4. Match it to the exam format. If the source describes a different question count, time limit, or fee than 75 questions, 90 minutes, and USD 125, it is describing a different exam.

If you are weighing the credential for career reasons, pay-related claims deserve the same skepticism. Earnings data tied to this designation is thin; the closest occupational proxy is the federal category Earth Drillers, Except Oil and Gas, which describes the occupation broadly rather than CVCLD holders specifically. See CVCLD Salary Guide 2026: Complete Earnings Analysis for how to read that proxy responsibly, and note that shallow ground-source heat-pump loop drilling is a different line of work from deep geothermal-power drilling.

If you want to confirm the details of the credential itself before investing, start with What Is CVCLD Certification? and, once you are ready to schedule, CVCLD Exam Dates 2026: Testing Windows, Deadlines & Scheduling.

The honest summary of the pass-rate question is this: there is no verified percentage to anchor to, but the documented structure points to a manageable exam for a prepared, experienced candidate: a 70% threshold, 90 minutes for 75 questions, immediate results, and unlimited-feeling retake access. Your best predictor of success is how completely your experience and preparation cover all ten duties, not an aggregate statistic. When you are ready to test yourself against the real format, start with the CVCLD practice tests.

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