- The Short Answer: Certified Well Driller
- Who Issues the Credential and Who Administers the Exam
- Why the Title Takes Two Exams, Not One
- What the General Drilling Exam Covers
- Choosing a Drilling-Method Specialty
- Eligibility, Fees, and Exam-Day Rules
- Voluntary NGWA Certification vs. State Licensing
- Keeping the Credential: Annual Renewal
- Sequencing Your Preparation
- Frequently Asked Questions
- CWD here means Certified Well Driller, a voluntary credential from the National Ground Water Association (NGWA).
- Earning CWD requires General Drilling plus at least one drilling-method specialty, each passed with 70% or higher within 12 months.
- The published fee is $75 per examination, so two first-attempt exams cost at least $150 before other fees.
- General Drilling has 50 multiple-choice questions in 60 minutes across six domains; Construct Water Well carries the most items.
The Short Answer: Certified Well Driller
On this site, CWD stands for Certified Well Driller. It is a professional credential for people who construct water wells, and it is issued through the National Ground Water Association (NGWA). If you landed here after seeing the acronym in a job posting, on a business card, or in a drilling-industry newsletter, that is the meaning you are looking for.
The acronym is shared with several unrelated terms and credentials elsewhere, which is why searches for it can be confusing. Nothing on this page applies to any of those. Everything below concerns the well-drilling credential specifically: what it signifies, how a driller earns it, and what keeping it involves. If you want a broader orientation first, our overview pieces What Is CWD? and CWD Meaning cover the same ground from different angles.
Who Issues the Credential and Who Administers the Exam
The National Ground Water Association runs the voluntary contractor certification program that includes Certified Well Driller. The examinations themselves are delivered by PSI Services as closed-book, computer-based tests at proctored testing centers. That means no reference materials in the room, no open-book lookups, and a supervised environment.
Two practical details are worth knowing early:
- A nonprinting, nonprogrammable calculator without an alphabetical keypad is permitted. Bring one you are comfortable with, because well-construction problems often involve volumes, annular spaces, and flow calculations.
- Scratch paper is supplied by the test center and collected at the end, so you cannot carry notes out of the room.
For the official source of record on current exam requirements and fees, NGWA maintains a certification exams page; always check it before you register, since details can change between editions of the candidate information bulletin.
Why the Title Takes Two Exams, Not One
This is the single most misunderstood feature of the credential. Passing one exam does not make you a Certified Well Driller. The pathway has two required components:
- General Drilling, the foundational exam covering the full well-construction lifecycle.
- At least one drilling-method specialty exam, chosen to match the way you actually drill.
Both must be passed within the same 12-month period, with at least 70% on each. General Drilling alone does not confer the CWD title. If you pass General Drilling and let the clock run out before passing a specialty, you have not completed the certification pathway as described in the program materials.
| Component | Format | Required Score |
|---|---|---|
| General Drilling | 50 multiple-choice questions, 60 minutes | 70% |
| Drilling specialty (most methods) | Normally 50 questions | 70% |
| Exam M, Augering and monitoring | 75 questions | 70% |
Note that 70% is the required score, not a pass rate. No current aggregate pass rate has been verified, so be skeptical of any site that quotes one with confidence. Our CWD pass rate article and CWD passing score guide explain how to interpret what is and is not known.
What the General Drilling Exam Covers
The General Drilling exam is organized around six formal objectives that follow a well from the moment a rig rolls onto the property to the moment it leaves. The published item allocations are counts of questions, not percentage weights, so treat them as a guide to emphasis rather than a precise formula.
| Domain | Published Item Count |
|---|---|
| Domain 1: Mobilize for the Site | 10 |
| Domain 2: Construct Water Well | 16 |
| Domain 3: Rehabilitate Wells | 5 |
| Domain 4: Develop Wells | 11 |
| Domain 5: Decommission Wells | 3 |
| Domain 6: Demobilize the Site | 5 |
Construct Water Well is the heaviest area by a clear margin. For a deeper walkthrough of each content area, see CWD Exam Domains 2026: Complete Guide to All 6 Content Areas.
Domain 1: Mobilize for the Site
This covers everything that must happen before drilling begins.
- Site evaluation, access, and staging of equipment
- Locating hazards such as utilities and overhead lines before setup
- Planning the job so materials and equipment match the intended well design
Domain 2: Construct Water Well
The largest block of the exam, and the one most directly tied to day-to-day drilling.
- Drilling and borehole advancement decisions
- Casing, screen, and annular-seal considerations
- Protecting the aquifer and the finished well from contamination
Domain 3: Rehabilitate Wells
Existing wells lose performance over time, and the exam expects you to recognize why and what to do about it.
- Diagnosing declining yield or water-quality problems
- Choosing appropriate rehabilitation approaches
Domain 4: Develop Wells
The second-largest allocation. Development is what turns a drilled hole into a productive well.
- Removing fines and drilling residue near the screen
- Methods for developing a well and recognizing when it is complete
Domain 5: Decommission Wells
The smallest allocation, but a topic with real regulatory and environmental consequences.
- Properly sealing abandoned wells to protect groundwater
- Documentation and procedures for taking a well out of service
Domain 6: Demobilize the Site
Finishing the job responsibly.
- Site restoration and cleanup
- Final records and handoff to the owner
Choosing a Drilling-Method Specialty
The second half of the pathway is a drilling-method specialty. Most specialty exams run about 50 questions, while Exam M, Augering and monitoring, has 75. Because the specialty must be passed within the same 12-month window as General Drilling, the choice should be deliberate rather than an afterthought.
How to pick the right one
- Match your daily work. Choose the method you actually perform in the field, since the questions will reward hands-on familiarity.
- Consider the longer exam. If Exam M is your method, plan for the larger question count and the extra stamina it demands.
- Check the current list. The available specialties are defined in NGWA's candidate information bulletin; confirm them there rather than relying on secondhand lists.
Plenty of candidates underestimate this half. They study the six General Drilling domains thoroughly and then treat the specialty as a formality. Our difficulty guide discusses why the combined pathway is harder than either exam seems on its own.
Eligibility, Fees, and Exam-Day Rules
Who can apply
Eligibility is experience-based, not classroom-based. Candidates must:
- Be 20 years of age or older
- Have 24 consecutive months of full-time drilling or pump-installation experience
- Provide two written professional references from people not affiliated with their current employer
- Submit the required agreement and a current-year affidavit
Application materials must arrive within 12 months of the qualifying examination session. For the complete breakdown, see CWD Requirements 2026: Eligibility, Prerequisites & How to Qualify.
What it costs
The published examination fee is $75 per examination, the same for members and nonmembers. Since CWD requires two exams, two first-attempt examinations cost at least $150. That figure is a floor, not a full budget. The candidate bulletin separately warns that nonmembers face an additional certification-application fee, though it does not state the amount. It also does not account for study materials, travel to a testing center, or retakes.
Voluntary NGWA Certification vs. State Licensing
A frequent point of confusion is whether Certified Well Driller replaces a state license. It does not. NGWA certification is voluntary, while licensing is a separate matter handled under state rules where applicable. The two serve different purposes:
| Aspect | NGWA Certified Well Driller | State Licensing |
|---|---|---|
| Nature | Voluntary professional credential | Legal authorization where required by the state |
| Issuing body | National Ground Water Association | State agency or board |
| Purpose | Demonstrates verified knowledge and experience | Permits you to operate legally |
| Replaces the other? | No | No |
Renewal of the NGWA credential even requires compliance with licensing requirements, so the two are linked in practice without being interchangeable. Whether the credential is worth pursuing in addition to any license you hold is a career question, which we examine in Is the CWD Certification Worth It? and, for the earnings side, CWD Salary Guide 2026.
Keeping the Credential: Annual Renewal
Certified Well Driller is not a one-and-done credential. Renewal is annual and involves:
- Seven continuing education points (CEPs)
- An affidavit
- Applicable fees
- Compliance with licensing requirements
The stated due date is December 31. The currently linked 2027 renewal form lists $50 for members and $150 for nonmembers. These are renewal fees and should never be confused with the $75 examination fee.
Key Takeaway
Sources conflict on late fees. The renewal webpage allows receipt through January 31 without a late fee, but the linked 2027 form says to add $50 after December 31. Do not rely on a grace period; confirm the applicable deadline with NGWA and submit by December 31.
Sequencing Your Preparation
Because the two exams must land within the same 12-month window, sequencing matters more than study technique. One workable approach ties the weeks to the domains by their weight and by the order in which a well is actually built:
Construct Water Well first
- It has the largest item allocation, so start where the most points live
- Work through borehole, casing, screen, and sealing concepts
Develop Wells and Mobilize for the Site
- The next two largest allocations
- Pair development methods with the planning decisions made at mobilization
Rehabilitate, Decommission, Demobilize
- Smaller allocations but easy points if you have reviewed them
- Decommissioning is small in count yet detail-heavy
Specialty exam
- Study your chosen drilling method separately; General Drilling prep does not cover it
- Take practice questions under timed, closed-book conditions
For supplemental reading, NGWA authored a General Drilling Exam Study Guide that maps preparation references to the same six headings. It does not supply complete specialty coverage, so treat it as a General Drilling aid only. Our CWD Study Guide expands on materials and pacing, and the CWD cheat sheet condenses the must-know facts onto one page. When you are ready to test yourself with original questions and explanations, try the CWD practice test.
Frequently Asked Questions
It stands for Certified Well Driller, a voluntary credential offered through the National Ground Water Association. It signals verified knowledge and experience in constructing water wells.
No. General Drilling alone does not confer the credential. You must also pass at least one drilling-method specialty exam, with both passed at 70% or higher within the same 12-month period.
General Drilling has 50 multiple-choice questions in 60 minutes. Most specialty exams normally have 50 questions, while Exam M, Augering and monitoring, has 75.
The published fee is $75 per examination for members and nonmembers, so two first-attempt exams cost at least $150. Nonmembers may also owe a certification-application fee whose amount is not stated in the bulletin, and this figure excludes preparation costs.
No. NGWA certification is voluntary and separate from state licensing. Renewing the credential does require compliance with applicable licensing requirements, but one does not substitute for the other.