- What "Hard" Actually Means for Certified Well Driller
- The Two-Exam Pathway: Where the Real Difficulty Lives
- Exam Format, Timing, and Testing Conditions
- Domain-by-Domain Difficulty Breakdown
- Choosing a Drilling Specialty
- Eligibility Hurdles Before You Even Sit
- Pass Rates and the 70% Score: Don't Confuse Them
- A Domain-Sequenced Prep Plan
- Cost, Retakes, and Renewal Pressure
- Frequently Asked Questions
- CWD requires two passed exams, General Drilling plus one drilling-method specialty, within the same 12-month period.
- Each exam needs at least 70%; passing General Drilling alone does not confer Certified Well Driller status.
- General Drilling is 50 multiple-choice questions in 60 minutes; Exam M (Augering and monitoring) has 75 questions.
- Construct Water Well carries the largest General Drilling allocation at 16 of 50 items.
What "Hard" Actually Means for Certified Well Driller
Ask ten drillers how hard the Certified Well Driller exam is and you will get ten different answers. A driller with a decade of rotary experience may find General Drilling comfortable and the specialty exam humbling. A newer candidate with two years in the field may find the opposite. The difficulty of the Certified Well Driller credential is not one number; it is a combination of factors: breadth of field knowledge, a closed-book computer-based format, a two-exam requirement, and a hard 12-month clock.
This guide breaks down each source of difficulty using the published NGWA program details so you can judge where you personally stand. If you want a full-length rundown of what each content area covers, pair this article with our CWD exam domains guide. To start testing yourself immediately, the CWD practice test is built around the same General Drilling headings.
The Two-Exam Pathway: Where the Real Difficulty Lives
The single most misunderstood fact about this credential is that one exam is not enough. To earn Certified Well Driller status, you must pass General Drilling and at least one drilling-method specialty, both within the same 12-month period, with at least 70% on each. General Drilling alone does not confer CWD.
That structure changes the difficulty calculation in three ways:
- You are studying for two exams, not one. The General Drilling content is documented in a published outline. The specialty you choose has its own content that you must source and prepare for separately.
- The clock is shared. Passing General Drilling in month one does not give you unlimited time to figure out the specialty. Both passes have to land within the same 12-month window.
- A strong result on one exam cannot rescue a weak result on the other. Each exam has its own 70% threshold.
For a full explanation of the pathway and prerequisites, see our CWD requirements guide.
Exam Format, Timing, and Testing Conditions
PSI Services administers the exams as closed-book, computer-based tests at proctored centers. You will not be flipping through a reference manual, so everything you rely on must be in your head.
| Exam | Questions | Time (where published) | Required Score |
|---|---|---|---|
| General Drilling | 50 multiple-choice | 60 minutes | At least 70% |
| Drilling specialty exams (typical) | 50 | Confirm in the current bulletin | At least 70% |
| Exam M, Augering and monitoring | 75 | Confirm in the current bulletin | At least 70% |
A few testing-day details matter for difficulty. A nonprinting, nonprogrammable calculator without an alphabetical keypad is permitted, which helps with volume, pressure, and grout calculations. Scratch paper is supplied and collected, so you cannot carry notes out. At 50 questions in 60 minutes, General Drilling gives you a little over a minute per item, which is workable for knowledgeable candidates but tight if you stall on calculation problems.
Domain-by-Domain Difficulty Breakdown
The General Drilling exam is organized around six formal objectives. Published item allocations across the 50 questions are 10, 16, 5, 11, 3, and 5, in the order below. These are item counts, not published percentage weights. Keep in mind these six headings describe General Drilling only; they are not a complete blueprint for the specialty exam you also need.
Domain 1: Mobilize for the Site (10 items)
Ten items is a substantial share of the exam, and this domain tests judgment before a bit ever turns. Expect questions on site evaluation, utility and hazard awareness, equipment selection, and getting set up safely and legally.
- Difficulty: moderate. Experienced drillers do well; newer candidates sometimes underestimate how much planning and regulatory awareness is tested.
- Common trap: answering from "how we do it at my shop" rather than from standard practice.
Domain 2: Construct Water Well (16 items)
The largest allocation and the highest-stakes domain. Sixteen of 50 items means this area alone can decide your outcome. It covers the core of the trade: drilling methods, borehole stability, casing, screens, filter packs, grouting, and sealing.
- Difficulty: high. Breadth is the problem; you need working knowledge of multiple methods and formations.
- Calculations (annular space, material quantities) concentrate here.
Domain 3: Rehabilitate Wells (5 items)
Five items, but the content is distinctive. Candidates who have mostly drilled new wells sometimes have thin knowledge of diagnosing and restoring declining production.
- Difficulty: moderate, with a high surprise factor for new-construction specialists.
Domain 4: Develop Wells (11 items)
The second-largest allocation. Development is where a finished borehole becomes a productive well, and the exam expects you to understand the methods, the reasoning behind them, and how to judge when development is complete.
- Difficulty: moderate to high. Many candidates know the techniques but struggle with the "why" behind method selection.
Domain 5: Decommission Wells (3 items)
The smallest allocation at three items. Do not skip it, though; at 3 items, each question is worth the same as in any other domain, and sealing and abandonment principles are conceptually learnable.
- Difficulty: low to moderate. Good return on a short study session.
Domain 6: Demobilize the Site (5 items)
Five items covering closeout: restoring the site, handling cuttings and fluids, documentation, and final steps.
- Difficulty: low to moderate. Easy points if you have reviewed it; unforced errors if you have not.
Looking at the allocations together, Construct Water Well (16) and Develop Wells (11) together account for 27 of the 50 items. That is more than half the exam concentrated in two domains, which should shape how you divide study time. Our CWD cheat sheet condenses the must-know facts across all six areas for quick review.
Choosing a Drilling Specialty
Because the General Drilling objectives do not cover the specialty requirement, your choice of drilling-method specialty is a difficulty lever you control. Most specialty exams run 50 questions, while Exam M (Augering and monitoring) has 75, meaning a longer sitting and more material to retain.
How to think about the choice
- Match your daily work. A specialty tied to the method you run every week lets your field memory do much of the heavy lifting.
- Consider question count. Exam M's 75 questions demand more endurance and broader recall than a 50-question specialty.
- Check the current bulletin first. Specialty content outlines are separate from the General Drilling outline, and the study guide mapped to the six General Drilling headings does not supply complete specialty coverage.
- Plan the 12-month window. Pick a specialty you can realistically prepare for before the shared clock runs out.
Key Takeaway
Do not pick a specialty by guessing which is "easiest" on forums. Pick the method you know best from actual field work, confirm its content outline in the current NGWA/PSI bulletin, and budget separate study time for it.
Eligibility Hurdles Before You Even Sit
For many candidates, the hardest part is qualifying to test at all. Eligibility requires:
- Age 20 or older
- 24 consecutive months of full-time drilling or pump-installation experience
- Two written professional references unaffiliated with your current employer
- The required agreement and a current-year affidavit
Application materials must also arrive within 12 months of the qualifying examination session. The reference requirement trips up some applicants: both references must come from people outside your current employer, which takes advance coordination. Details on each prerequisite are in our eligibility and prerequisites guide, and scheduling specifics are covered in CWD exam dates and deadlines.
Pass Rates and the 70% Score: Don't Confuse Them
Searches for "how hard is the CWD exam" almost always lead people to look for a pass rate. Here is the honest answer: no current aggregate CWD pass rate was verified for this guide. Any specific percentage you see quoted without a clear NGWA or PSI source should be treated as unreliable.
What is verified is the required examination score: at least 70% on each exam. That is a passing threshold, not a statistic about how many candidates succeed. On a 50-question exam, 70% means answering 35 correctly; on Exam M's 75 questions, 70% means 53 correct answers (52.5 rounded up). For more on how scoring works, see our CWD passing score explainer and the discussion in what the data shows about CWD pass rates.
A Domain-Sequenced Prep Plan
Generic study advice will not serve you here. What matters is sequencing the six General Drilling domains by item allocation and by how likely they are to expose gaps, then layering in the specialty. The timeline below assumes an eight-week window for General Drilling; add specialty study afterward or in parallel, depending on your schedule.
Construct Water Well
- Start with the 16-item domain while energy is highest
- Drill the calculations until you can do them quickly on a basic calculator
- Review method-specific behavior across different formations
Develop Wells
- Cover the 11-item domain: methods, reasoning, and completion criteria
- Connect development choices back to construction decisions from earlier weeks
Mobilize for the Site and Rehabilitate Wells
- 10 items from mobilization plus 5 from rehabilitation
- Give extra time to rehabilitation if you mostly drill new wells
Decommission Wells and Demobilize the Site
- Quick wins: 3 plus 5 items
- Review sealing principles and closeout documentation
Timed Practice
- Run full 50-question sets against the 60-minute limit
- Review every miss by domain to find your weakest area
For reference material, the NGWA-authored General Drilling Exam Study Guide maps preparation references to the same six headings, which makes it a natural companion to the plan above. Remember that it does not supply complete specialty coverage. Our CWD study guide walks through additional resources, and CWD training options covers structured courses if you prefer instructor-led prep.
Cost, Retakes, and Renewal Pressure
Difficulty has a financial dimension. The published examination fee is $75 per examination for members and nonmembers, so two first-attempt exams cost at least $150. That figure is not an all-inclusive budget: the candidate bulletin separately warns of an additional certification-application fee for nonmembers without stating the amount, and it excludes preparation materials entirely. A failed attempt means paying the exam fee again, and the shared 12-month window keeps retake timing from drifting.
Once certified, the work continues. Renewal is annual and requires seven continuing education points (CEPs), an affidavit, applicable fees, and compliance with licensing requirements, with a stated due date of December 31. The currently linked 2027 renewal form lists $50 for members and $150 for nonmembers; those are renewal fees, not exam fees. There is also a conflict to watch: the renewal webpage allows receipt through January 31 without a late fee, while the linked form says to add $50 after December 31. Confirm the applicable deadline rather than assuming a grace period.
| Item | Verified Detail |
|---|---|
| Exam fee | $75 per exam; at least $150 for two first attempts |
| Nonmember application fee | Exists per the bulletin; amount not published there |
| Annual renewal (2027 form) | $50 members, $150 nonmembers |
| Renewal requirement | 7 CEPs, affidavit, fees, licensing compliance |
| Renewal due date | December 31 (confirm late-fee rules) |
For the full picture, see our CWD certification cost breakdown. If you are weighing whether the investment pays off, read whether the CWD certification is worth it and the CWD salary guide.
Voluntary certification versus state licensing
One more source of confusion that makes the credential feel harder than it is: NGWA certification is voluntary and separate from state licensing. Your state may require its own license to drill, with its own exam and requirements. Earning Certified Well Driller does not replace that license, and renewal explicitly requires compliance with licensing requirements. Treat the two as parallel tracks that reinforce each other, not as substitutes.
Frequently Asked Questions
No. CWD requires General Drilling and at least one drilling-method specialty, both passed within the same 12-month period with at least 70% on each. General Drilling alone does not confer the credential.
General Drilling has 50 multiple-choice questions in 60 minutes. Drilling specialty exams normally have 50 questions, while Exam M, Augering and monitoring, has 75. Confirm specialty time limits in the current candidate bulletin.
No current aggregate CWD pass rate was verified. The 70% figure is the required score on each exam, not the percentage of candidates who pass. Be skeptical of any pass-rate number without a clear NGWA or PSI source.
Construct Water Well has the largest allocation at 16 of 50 items, followed by Develop Wells at 11 and Mobilize for the Site at 10. Together, the top two domains account for more than half the exam.
Yes. A nonprinting, nonprogrammable calculator without an alphabetical keypad is permitted. Scratch paper is supplied and collected afterward, so plan on doing your working during the test itself.
Ready to see where you stand? Take a timed set on the CWD practice test, then review your results against the six General Drilling domains to decide where your next study session should go.