- The Two-Exam Pathway: Why One Passing Score Is Not Enough
- Confirm Eligibility Before You Spend a Dollar
- Exam Format, Fees, and Test-Day Rules
- The Six General Drilling Domains and Their Item Counts
- What to Master Inside Each Domain
- Choosing Your Drilling-Method Specialty
- Original Practice Questions With Explanations
- A Domain-Ordered Study Sequence
- NGWA Certification Versus State Licensing
- Staying Certified: Annual Renewal Mechanics
- Frequently Asked Questions
- CWD requires General Drilling plus at least one drilling-method specialty, each scoring 70% or higher within the same 12-month period.
- General Drilling has 50 multiple-choice questions in 60 minutes; most specialty exams also have 50, but Exam M has 75.
- Each exam costs $75, so two first-attempt exams total at least $150 before any application fee.
- Construct Water Well carries the most General Drilling items (16 of 50), so it deserves your largest block of study time.
The Two-Exam Pathway: Why One Passing Score Is Not Enough
The most common planning mistake with the Certified Well Driller credential from the National Ground Water Association (NGWA) is treating it as a single test. It is not. To earn CWD, you must pass the General Drilling examination and at least one drilling-method specialty examination, and both must be passed within the same 12-month period, each with a score of at least 70%. Passing General Drilling alone does not confer the credential.
That structure shapes everything about a first-attempt strategy. You are preparing for two closed-book, computer-based exams administered by PSI Services at proctored testing centers, and the specialty you choose determines half of your preparation load. If you want the broader picture of what the credential means before diving into study planning, start with our overview of what CWD certification is, then return here for the preparation plan.
Confirm Eligibility Before You Spend a Dollar
Exam fees are only part of the commitment. NGWA sets experience and documentation requirements that you should verify first. Based on the published criteria, you need:
- To be age 20 or older
- 24 consecutive months of full-time drilling or pump-installation experience
- Two written professional references from people not affiliated with your current employer
- The required agreement and a current-year affidavit
- Application materials that arrive within 12 months of the qualifying examination session
The "unaffiliated with your current employer" detail trips up more candidates than people expect. If your only professional contacts work at your company, start identifying a supplier, inspector, engineer, or former colleague well before you need the paperwork. Our full breakdown in CWD Requirements 2026: Eligibility, Prerequisites & How to Qualify walks through each item in more detail.
Exam Format, Fees, and Test-Day Rules
Knowing the mechanics removes avoidable stress. Here is what the published materials establish:
| Item | General Drilling | Drilling Specialty Exams |
|---|---|---|
| Questions | 50 multiple-choice | Normally 50; Exam M (Augering and monitoring) has 75 |
| Time allowed | 60 minutes | Confirm the time limit for your specific specialty in the candidate bulletin |
| Passing score | 70% minimum | 70% minimum |
| Exam fee | $75 | $75 per examination |
| Delivery | Closed-book, computer-based, PSI Services proctored centers | |
At $75 per exam for both members and nonmembers, two first-attempt exams cost at least $150. That 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. Check the current NGWA fee pages before you budget, and see CWD Certification Cost 2026: Complete Pricing Breakdown for how the pieces fit together.
Calculator and scratch paper
You may use a nonprinting, nonprogrammable calculator without an alphabetical keypad. Scratch paper is supplied and collected at the end. Since drilling work involves volume, annular space, and grout-quantity math, practice with the same kind of basic calculator you will bring rather than relying on a phone or spreadsheet during preparation.
For scheduling specifics, including how testing windows interact with application deadlines, see CWD Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
The Six General Drilling Domains and Their Item Counts
The General Drilling exam is organized around six formal objectives. NGWA publishes item allocations, meaning actual question counts, rather than percentage weights, so the numbers below are counts out of the 50 questions:
| Domain | Published Items |
|---|---|
| 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 |
Two things stand out. First, Construct Water Well holds the largest allocation by a wide margin. Second, Domains 1 and 4 together account for 21 items, which is more than many candidates assume given how routine mobilization can feel in the field. A candidate who studies only construction and ignores site setup and well development is leaving a large share of the exam to chance.
What to Master Inside Each Domain
Domain 1: Mobilize for the Site (10 items)
Questions here test whether you can prepare a job safely and correctly before the bit touches the ground.
- Utility locating and clearance requirements before breaking ground
- Site safety planning, equipment positioning, and hazard recognition
- Material and equipment staging, including water source and drilling fluid containment
- Understanding permitting and regulatory notification steps that apply to your jurisdiction
Domain 2: Construct Water Well (16 items)
The heart of the exam and your biggest return on study time.
- Selecting casing, screen, and filter-pack materials appropriate to the formation
- Annular seal and grouting: placement methods, materials, and why they protect the aquifer
- Borehole and casing sizing relationships and the calculations that follow from them
- Drilling fluid properties and how they affect borehole stability
- Wellhead completion and protection against surface contamination
Domain 3: Rehabilitate Wells (5 items)
Fewer items, but they reward candidates who understand why wells lose performance.
- Recognizing causes of declining yield, such as biofouling, scaling, and screen plugging
- Matching a rehabilitation approach to the diagnosed problem
- Chemical and mechanical treatment safety and disposal considerations
Domain 4: Develop Wells (11 items)
Development is where a finished borehole becomes a productive well.
- Purpose of development: removing fines, repairing drilling damage, and stabilizing the filter pack
- Common development methods and when each is appropriate
- Judging when development is complete, including sediment and water-clarity indicators
Domain 5: Decommission Wells (3 items)
The smallest allocation, but the concepts are tightly testable.
- Why abandoned wells are a contamination pathway to groundwater
- Sealing materials and placement principles
- Documentation and regulatory compliance for abandonment
Domain 6: Demobilize the Site (5 items)
Closing a job correctly is a professional and environmental obligation.
- Site restoration, cuttings and fluid handling, and waste disposal
- Record keeping, including well logs and completion reports
- Final equipment decontamination and safety checks
NGWA's own General Drilling study guide, which maps preparation references to these same six headings, is a useful supplement. It covers General Drilling only and does not supply complete specialty coverage, so use it alongside, not instead of, specialty-specific materials.
Choosing Your Drilling-Method Specialty
Because CWD requires at least one drilling-method specialty, your choice deserves deliberate thought. The specialty exams are tied to drilling methods, and one example from the published materials is Exam M, Augering and monitoring, which has 75 questions rather than the usual 50. That difference alone changes your pacing and stamina planning.
- Choose the method you work with daily. Field familiarity makes terminology and scenario questions far more intuitive.
- Check the question count and time limit for your chosen specialty in the candidate bulletin before you schedule.
- Consider your employer's equipment fleet. A specialty you can practice on the job is easier to retain.
- Remember it is a separate exam. The General Drilling domains will not cover it, so budget separate study weeks.
Key Takeaway
Pick your specialty before you finish studying General Drilling, not after. Content overlaps in places, and knowing your second exam early lets you collect specialty references while you are already in study mode.
Original Practice Questions With Explanations
The following original questions mirror the multiple-choice, scenario-driven style of General Drilling. They are study illustrations, not actual exam items. For a larger bank, use the full CWD practice test on the main site.
Question 1 (Domain 1: Mobilize for the Site)
Before positioning a rig on a new residential site, which action should be completed first?
- Mix drilling fluid additives
- Arrange for underground utilities to be located and marked
- Unload casing and screen
- Set up the mud pit
Answer: B. Utility locating comes before any ground disturbance or heavy equipment positioning. Striking a buried line is a life-safety and liability risk, which is why clearance precedes material staging.
Question 2 (Domain 2: Construct Water Well)
What is the primary purpose of placing a grout seal in the annular space of a completed well?
- To increase well yield
- To support the screen
- To prevent surface water and shallow contaminants from migrating down the borehole
- To reduce drilling time
Answer: C. The annular seal blocks vertical movement of contaminants along the outside of the casing. It protects the aquifer rather than improving production.
Question 3 (Domain 4: Develop Wells)
A newly drilled well continues to produce sandy water after initial pumping. What does this most likely indicate?
- Development is incomplete and fines remain to be removed
- The well is ready for service
- The casing is too large
- The grout has cured
Answer: A. Persistent sediment signals that development has not yet stabilized the filter pack and removed fine material. Delivering water that is still sandy risks pump damage and an unhappy customer.
Question 4 (Domain 5: Decommission Wells)
Why must unused wells be properly decommissioned?
- They lose value as property
- They can act as direct conduits for contamination to reach groundwater
- They increase local water pressure
- They must be reused within five years
Answer: B. An open, abandoned borehole offers a pathway from the surface or from shallow zones into an aquifer. Proper sealing removes that pathway.
A Domain-Ordered Study Sequence
Rather than a generic schedule, order your preparation by where the exam's points are. Here is an example plan keyed to the published item counts:
Domain 2: Construct Water Well
- Spend the most time here; it is 16 of 50 items
- Drill the grouting, casing, and fluid concepts until you can explain the reasoning
- Practice the sizing and volume calculations with your exam-permitted calculator
Domains 1 and 4: Mobilization and Development
- Together these account for 21 items
- Review utility clearance, site safety, and development end-point indicators
Domains 3, 5, and 6
- Cover rehabilitation, decommissioning, and demobilization (13 items combined)
- Focus on cause-and-effect reasoning and documentation duties
Specialty Exam Preparation
- Switch fully to your chosen drilling-method specialty
- Take timed practice sets that match its question count
Adjust the timeline to your experience. A veteran driller may compress the first domains and spend longer on weaker areas such as rehabilitation chemistry. For a quick-reference companion while you study, see the CWD Cheat Sheet 2026: One-Page Review of Must-Know Facts, and for a realistic read on how demanding the exams are, read How Hard Is the CWD Exam? Complete Difficulty Guide 2026.
NGWA Certification Versus State Licensing
A frequent point of confusion: CWD is a voluntary certification from NGWA, not a government license. State licensing, where required, is a separate legal matter handled by state agencies, and requirements vary by jurisdiction. Holding CWD does not replace any license your state demands, and renewal of the certification explicitly requires compliance with licensing requirements.
| Aspect | NGWA CWD | State License |
|---|---|---|
| Nature | Voluntary professional credential | Legal authorization to operate (where required) |
| Issued by | National Ground Water Association | State or local authority |
| Replaces the other? | No. Keep both current as your jurisdiction requires. | |
The practical value of CWD is professional recognition and a demonstrated standard of knowledge, which many employers and customers notice. If you are weighing whether it fits your career, our analysis in Is the CWD Certification Worth It? Complete ROI Analysis 2026 and the CWD Salary Guide 2026 cover the earnings and career questions without relying on invented figures.
Staying Certified: Annual Renewal Mechanics
Earning CWD is only the first milestone. 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. These are renewal fees, not examination fees, so do not confuse them with the $75 exam charge.
Building CEP accumulation into your year, rather than scrambling in December, is the simplest way to avoid trouble. Looking ahead to career options after certification? See CWD jobs for the kinds of employers and roles that value the credential.
Frequently Asked Questions
No. The requirement is that General Drilling and at least one drilling-method specialty are both passed within the same 12-month period, each with at least 70%. They do not have to be taken on the same day.
General Drilling has 50 multiple-choice questions with a 60-minute time limit. Most specialty exams also have 50 questions, but Exam M (Augering and monitoring) has 75.
The published fee is $75 per examination for both members and nonmembers, so two first-attempt exams cost at least $150. Nonmembers may also owe a separate certification-application fee, and the amount is not stated in the candidate bulletin, so confirm it with NGWA.
No. Seventy percent is the minimum score required on each exam, not a pass rate. No current aggregate pass rate has been verified; see CWD Pass Rate 2026: What the Data Shows and CWD Passing Score 2026 for more context.
Yes, a nonprinting, nonprogrammable calculator without an alphabetical keypad is permitted. Scratch paper is supplied and collected at the end of the exam.
With a clear view of the two-exam pathway, the six General Drilling domains, and your chosen specialty, you can build a preparation plan that targets points rather than hours. For an overview of the credential's training landscape, see CWD training, and revisit the CWD Study Guide 2026 as your central reference while you prepare.