- The Short Answer: CWD Means Certified Well Driller
- Who Issues the Credential and What It Is (and Is Not)
- Why the Title Takes Two Exams
- What the General Drilling Exam Covers
- Choosing a Drilling-Method Specialty
- Who Qualifies to Sit for the Exams
- Fees, Testing Format, and Exam-Day Rules
- Voluntary Certification vs. State Licensing
- Sample Practice Questions with Explanations
- Keeping the Credential: Annual Renewal
- Mapping Your Preparation to the Domains
- Frequently Asked Questions
- CWD stands for Certified Well Driller, a voluntary credential from the National Ground Water Association (NGWA).
- You must pass General Drilling plus at least one drilling-method specialty within the same 12-month period.
- Each exam requires a score of at least 70%, and General Drilling alone does not confer CWD.
- The published exam fee is $75 per examination, so two first attempts cost at least $150.
The Short Answer: CWD Means Certified Well Driller
On this site, CWD means Certified Well Driller. It is a professional credential for people who drill water wells and install pumps, offered through the National Ground Water Association (NGWA). If you have seen the same three letters attached to other credentials or topics elsewhere online, set those aside. Everything in this article refers only to the NGWA well-driller certification and the exams that lead to it.
The title describes a specific, verified level of competence: a driller who has documented field experience, supplied professional references, and passed closed-book, proctored examinations covering both general drilling practice and at least one drilling method. It is a credential earned by working drillers, not an entry-level classroom certificate.
If you want a broader orientation before diving into the details here, our overview pages on what CWD certification is and CWD meaning cover the same ground from slightly different angles.
Who Issues the Credential and What It Is (and Is Not)
The NGWA runs the Voluntary Certification Program under which the Certified Well Driller title is awarded. PSI Services administers the examinations as closed-book, computer-based tests at proctored testing centers. The word voluntary matters: no federal rule requires a driller to hold this credential, and it does not replace any license your state may demand.
Employers that value the credential tend to be water well contracting companies, drilling firms that also install pumps and perform rehabilitation or decommissioning work, and operations that want a visible, third-party-verified benchmark of competence on their crews. Whether the credential pays off for you personally is a separate question, which we address in Is the CWD Certification Worth It? and, on the earnings side, in the CWD salary guide.
Why the Title Takes Two Exams
This is the single most misunderstood feature of the credential. You do not become a Certified Well Driller by passing one test. The pathway requires:
- The General Drilling exam, and
- At least one drilling-method specialty exam,
with both passed within the same 12-month period and a score of at least 70% on each. Passing General Drilling by itself does not confer CWD. Candidates who assume the general exam is the whole job often discover this only after they have already paid for and passed it, so it pays to plan both exams as a single project.
| Component | What It Is | Format Notes |
|---|---|---|
| General Drilling | Core exam covering site-to-site drilling operations | 50 multiple-choice questions in 60 minutes |
| Drilling specialty (typical) | Method-specific exam | Normally 50 questions |
| Exam M: Augering and monitoring | Specialty exam | 75 questions |
| Passing requirement | Each exam individually | At least 70% on each |
Note that 70% is the required score, not a pass rate. We have not verified any current aggregate pass rate for this credential, and you should be skeptical of any site that quotes one without a source. For a frank look at what is and isn't known, see our CWD pass rate article, and for the cut-score mechanics see CWD passing score.
What the General Drilling Exam Covers
The General Drilling exam is organized around six formal objectives. The published item allocations are counts of questions, not percentage weights, so we do not convert them to percentages. Here is each area, with its allocated item count and what candidates should be ready to demonstrate.
Domain 1: Mobilize for the Site (10 items)
Everything that happens before the bit touches the ground.
- Site assessment, access, and utility awareness
- Equipment readiness and transport considerations
- Safety setup and planning prior to drilling
Domain 2: Construct Water Well (16 items)
The largest allocation on the exam, and the heart of the trade.
- Drilling operations and borehole advancement
- Casing, screen, and annular materials placement
- Grouting and sealing practices that protect the aquifer
- Documenting what you encounter downhole
Domain 3: Rehabilitate Wells (5 items)
Restoring performance to an existing well.
- Recognizing signs of declining yield or deteriorating condition
- Selecting appropriate rehabilitation approaches
Domain 4: Develop Wells (11 items)
Preparing a newly constructed well to produce properly.
- Methods for removing fine material near the screen
- Judging when development is adequate
Domain 5: Decommission Wells (3 items)
Properly abandoning wells that are no longer in service.
- Sealing practices that prevent contaminant pathways
- Documentation of the abandonment
Domain 6: Demobilize the Site (5 items)
Leaving the property safe and compliant.
- Cleanup and restoration
- Final records and wrap-up
These six headings are the formal General Drilling objectives. They are not a complete blueprint for the additional specialty you need for CWD. The specialty exam has its own content, so budget study time for it separately. For a deeper breakdown of each content area, read our complete guide to all six CWD exam domains.
Key Takeaway
Construct Water Well carries the largest item allocation (16 items), followed by Develop Wells (11) and Mobilize for the Site (10). Weight your hours accordingly, but do not neglect the 3-item Decommission Wells domain: on a 50-question, 70%-to-pass exam, every missed cluster matters.
Choosing a Drilling-Method Specialty
The specialty you pick should match the work you actually do, because you will be tested on method-specific practice that only makes sense if you have hands-on familiarity. Some practical considerations:
- Pick what you drill. A specialty tied to a method you use daily lets you lean on field memory instead of memorizing from scratch.
- Check the question count. Most specialty exams normally run 50 questions, but Exam M (Augering and monitoring) has 75, which changes your pacing and stamina plan.
- Confirm the current list. Specialty offerings are published by NGWA; verify the up-to-date list on the NGWA certification exams page before committing.
- Remember the clock. Both exams must be passed within the same 12-month period, so do not schedule the specialty so late that a retake would fall outside the window.
Adding a second specialty is optional for CWD but may broaden what your credential demonstrates. Ask your employer which methods their customers and regulators care about most.
Who Qualifies to Sit for the Exams
Eligibility is concrete and documented. According to the NGWA requirements, candidates need:
- To be age 20 or older
- 24 consecutive months of full-time drilling or pump-installation experience
- Two written professional references from people unaffiliated with your current employer
- The required agreement signed
- A current-year affidavit
Application materials must arrive within 12 months of the qualifying examination session. That timing detail trips people up: a stale file is not a quick fix. We walk through preparing each document in CWD requirements: eligibility, prerequisites, and how to qualify, and the scheduling side is covered in CWD exam dates.
Fees, Testing Format, and Exam-Day Rules
The published examination fee is $75 per examination, the same for members and nonmembers. Because the pathway requires two exams, two first-attempt sittings cost at least $150. That figure is a floor, not a total certification budget.
On exam day, expect these rules:
- Closed-book, computer-based testing at a proctored PSI center
- A nonprinting, nonprogrammable calculator without an alphabetical keypad is permitted
- Scratch paper is supplied and collected when you finish
The calculator allowance is worth practicing with. Drilling math, such as volumes, grout quantities, and flow conversions, is routine, and a calculator you have never used under time pressure is a liability. Practice with the same style of device you will bring.
Voluntary Certification vs. State Licensing
| Feature | NGWA Certified Well Driller | State Drilling License |
|---|---|---|
| Issued by | NGWA Voluntary Certification Program | State or local licensing authority |
| Legal requirement to work | No, voluntary | Often yes, depending on jurisdiction |
| Portability | National credential | Tied to the issuing state |
| Renewal | Annual, with 7 CEPs and an affidavit | Set by each state |
The two are complementary. Renewal of the CWD even requires compliance with licensing requirements, so letting a state license lapse can create trouble for your certification. When someone asks whether they "need" CWD to drill legally, the honest answer is: check your state rules, because the credential itself is not the legal gate.
Sample Practice Questions with Explanations
The questions below are original, written to mirror the style of the General Drilling categories. They are study aids, not actual exam items. For many more, use the full CWD practice test.
Practice Question: Mobilize for the Site
Before moving a rig onto a new property, which action most directly reduces the risk of striking a buried hazard?
- A. Starting the borehole slowly and watching for resistance
- B. Locating and marking underground utilities before breaking ground
- C. Choosing the lightest rig available
- D. Asking the landowner to guess where lines run
Answer: B. Utility location happens before any ground disturbance. Watching for resistance (A) is reactive and may be too late, and equipment weight (C) and guesswork (D) do not verify what is underground.
Practice Question: Construct Water Well
What is the primary purpose of placing grout in the annular space of a completed well?
- A. To increase the borehole diameter
- B. To make the casing easier to pull later
- C. To seal the annulus and block pathways for surface contamination
- D. To cool the drilling fluid
Answer: C. Annular sealing protects the aquifer by preventing surface water and contaminants from migrating down along the casing. The other options describe effects grouting does not provide.
Practice Question: Develop Wells
Why is development performed on a newly constructed well?
- A. To remove fine material near the screen and improve the well's ability to produce water
- B. To meet paperwork requirements only
- C. To lower the static water level permanently
- D. To add more casing
Answer: A. Drilling disturbs the formation near the screen. Development clears fines and settles the filter pack so the well can yield properly and avoid pumping sediment.
Practice Question: Decommission Wells
What is the central goal when decommissioning an unused well?
- A. Leaving the casing open for future inspection
- B. Sealing the well so it cannot act as a conduit for contamination
- C. Removing the wellhead for scrap value
- D. Filling the top foot with topsoil only
Answer: B. An abandoned open or poorly sealed borehole can carry surface contaminants to groundwater. Proper sealing eliminates that pathway, and the work should be documented.
Keeping the Credential: Annual Renewal
Certification is not a one-time event. Renewal is annual and requires seven continuing education points (CEPs), an affidavit, applicable fees, and compliance with licensing requirements. The stated renewal due date is December 31.
The currently linked 2027 renewal form lists $50 for members and $150 for nonmembers. Those are renewal fees, not examination fees, so keep the two budgets separate.
Mapping Your Preparation to the Domains
Because you are preparing for two exams, a domain-driven schedule works better than generic cramming. One workable arrangement over several weeks:
Mobilize and Demobilize
- Cover the bookend domains first; they are the most intuitive for working drillers
- Take a baseline practice set to see where you stand
Construct Water Well
- Spend the most time here: it has the largest item allocation
- Work calculation problems with your approved calculator
Develop, Rehabilitate, Decommission
- Group these related well-lifecycle topics
- Review sealing and documentation concepts together
Specialty Exam and Timed Review
- Shift to your chosen drilling-method specialty
- Run timed full-length sets: 50 questions in 60 minutes for General Drilling
For supplemental reading, an NGWA-authored General Drilling Exam Study Guide (undated, distributed in June 2025 through the Empire State Water Well Drillers Association) maps preparation references to the same six headings. Be aware it does not supply complete specialty coverage, so you will need separate materials for your specialty. Our CWD study guide and one-page CWD cheat sheet help consolidate this, and if you are wondering about difficulty, how hard the CWD exam is sets realistic expectations. When you are ready to test yourself, start at our main practice test site.
Frequently Asked Questions
On this site, CWD stands for Certified Well Driller, a voluntary professional credential offered through the National Ground Water Association (NGWA). It applies to people who drill water wells and install pumps.
No. CWD requires General Drilling plus at least one drilling-method specialty exam, both passed within the same 12-month period with at least 70% on each. General Drilling alone does not confer the title.
The published fee is $75 per examination for members and nonmembers, so two first-attempt exams cost at least $150. Nonmembers may also face an additional certification-application fee whose amount the bulletin does not specify, so confirm with NGWA.
Not necessarily. CWD is voluntary and does not replace state licensing. Whether you need a license to drill depends on your state or local rules, so check with the relevant licensing authority.
Renewal is annual, requiring seven continuing education points, an affidavit, applicable fees, and licensing compliance. The stated due date is December 31. Because sources conflict on late fees, confirm the deadline rather than relying on a grace period.