Exam E/F is a 50-question, one-hour, closed-book specialized drilling exam with a 70 percent minimum passing score, and it counts toward the Certified Well Driller designation together with the general drilling exam. Its content outline puts 35 of 50 questions on drilling fluids and well construction, so study those areas first, understand normal versus reverse circulation from first principles, and confirm eligibility and scheduling directly with NGWA and PSI.
Where Exam E/F fits in the Certified Well Driller path
Exam E/F: Mud Rotary Drilling is one of the specialized drilling exams in NGWA's voluntary certification program. To earn the Certified Well Driller (CWD) designation, you must pass the general drilling exam plus at least one specialized drilling exam, both within a single 12-month period at 70 percent or better.
NGWA has run this voluntary certification program since 1970, and it is governed by groundwater contractors. Several state agencies use the same tests inside their own licensing programs, but NGWA certification itself is a professional credential, not a license to drill.
E/F is one of several specialized drilling options. You choose whichever specialized exam matches your method, so mud rotary drillers normally pair the general exam with E/F.
| Drilling exam | Role toward CWD |
|---|---|
| General drilling exam | Required for every CWD candidate |
| Exam A/B: Cable tool drilling | Specialized option — choose one |
| Exam C/D: Air rotary drilling | Specialized option — choose one |
| Exam E/F: Mud rotary drilling | Specialized option — choose one |
| Exam G: Reverse circulation drilling | Specialized option — choose one |
| Exam H: Jetting and driving wells | Specialized option — choose one |
| Exam M: Augering and monitoring (75 questions) | Specialized option — choose one |
Sources: NGWA Certification exams (contractor certification) — Exam categories, preparation materials, and test center information; NGWA Certification for contractors — Program overview and eligibility requirements
Exam format and what to expect on test day
Exam E/F has 50 questions, a one-hour time limit, and a 70 percent minimum passing score. All NGWA exams are closed book, so no references go into the testing room with you.
PSI administers the exams at more than 400 test centers, and you can schedule year-round through PSI's website. Scores are issued immediately when you finish, so collect your score report at the center before leaving. All centers are ADA compliant, and accommodation requests go through NGWA, which then approves them with PSI.
You do not need NGWA approval before sitting an exam — eligibility for the certification itself is a separate matter handled through the application process described later.
Sources: NGWA Certification exams (contractor certification) — Exam categories, preparation materials, and test center information; PSI NGWA candidate information bulletin — Visually checked NGWA content tables, content pages 5–7 (May 2022)
The E/F content outline, question by question
The verified outline for Exam E/F spreads its 50 questions across five duty areas, and the weight sits clearly on drilling fluids and well construction.
The PSI bulletin dated September 2022 allocates 18 questions to well construction and 17 to preparing and managing drilling fluids. Together they account for 35 of 50 questions. Use that allocation, along with your own weak areas, to decide where to spend revision time.
Cover all five areas. A smaller question allocation does not make development or demobilization optional.
| Content area | Questions |
|---|---|
| Mobilize for the site | 9 |
| Construct water well | 18 |
| Prepare and manage drilling fluids | 17 |
| Develop wells | 5 |
| Demobilize the site | 1 |
How mud rotary circulation actually works
In the normal rotary method, fluid circulates down the drill pipe and back up the annular space, serving two jobs at once: cooling the bit and carrying rock cuttings out of the hole.
The hydraulic rotary method excavates the hole by rotating drill pipe fitted with a drag or roller bit. Water containing clay — the mud — is pumped down the drill pipe in the normal rotary method and returns up the annular space between the pipe and the borehole wall.
Reverse rotary flips the route: fluid goes down the annular space and comes back up the drill pipe. That direction distinguishes it from normal rotary circulation. NGWA lists reverse circulation separately as Exam G.
Air rotary is closely related but uses compressed air instead of mud as the drilling fluid. That contrast is a clean way to remember what defines the mud rotary category: the fluid itself.
Practice
A drilling report states that fluid was circulated down the annular space and returned up the drill pipe. Based on how the two rotary routes are defined, which method does this describe — normal rotary or reverse rotary?
Show answer
Reverse rotary.
The normal rotary route sends fluid down the drill pipe and returns it up the annular space. The report describes exactly the opposite path — down the annulus, up the pipe — which is the reverse rotary method. Route direction, not the fluid type alone, is what distinguishes the two names.
Sources: USGS Water-Supply Paper 2220: Basic Ground-Water Hydrology (1983) — Selected fundamentals on well construction methods and well development; NGWA Certification exams (contractor certification) — Exam categories, preparation materials, and test center information
Well development after a mud-rotary hole
Well development is the phase that removes clay, silt, and fine-grained sand from beside the screen or open hole so the finished well yields sediment-free water.
The development objective is different from excavating the borehole: it concerns fine material beside the screen or open hole. The E/F outline assigns five questions to well development.
Sources: USGS Water-Supply Paper 2220: Basic Ground-Water Hydrology (1983) — Selected fundamentals on well construction methods and well development; PSI NGWA candidate information bulletin — Visually checked NGWA content tables, content pages 5–7 (May 2022)
Eligibility and the certification application
To apply for NGWA certification you must be at least 20 years old, have 24 consecutive months of full-time drilling experience, pass your two required exams within one 12-month period at 70 percent or better, and submit references and signed paperwork.
The two professional references verifying your experience must come from contacts who are not affiliated with your current company. Along with them you submit an agreement form and an affidavit for the current year.
Timing matters twice over. Your general and specialized exams must both be passed within one 12-month period, and your completed application materials must be received within 12 months of the qualifying exam session. Schedule both exams with that window in mind rather than spacing them across two certification years.
- At least 20 years old
- 24 consecutive months of full-time drilling or pump installation experience
- Both required exams passed within one 12-month period, each at 70 percent or better
- Two written experience references from contacts outside your current company
- Agreement form and current-year affidavit submitted within 12 months of the qualifying exam session
Sources: NGWA Certification for contractors — Program overview and eligibility requirements; PSI NGWA candidate information bulletin — Visually checked NGWA content tables, content pages 5–7 (May 2022)
Study materials and a sensible sequence
NGWA names specific texts for the drilling exams, offers self-paced online training, and publishes DACUM task charts — use those official materials first, then structure your review around the blueprint weights.
For all drilling exams, NGWA recommends Groundwater & Wells (third edition), the Manual of Water Well Construction Practices (third edition), the Water Well Driller's Beginning Training Manual, and the Procedures for Well Drilling Operations CD, plus the Professional Designations Information and Study Guide covering every exam. The NGWA Exam Preparation Success Guide gives an overview of how and what to study. NGWA University's online courses for the general drilling exam were built with subject-matter experts and include study guides and knowledge checks.
The DACUM charts for drilling contractors and operators are worth a look, with one caution: they are job-task analyses listing the duties, tools, and knowledge of the trade — not exam questions and not procedures. The duty letters in the chart do not correspond to exam letters, so do not try to map them onto Exam E/F's outline.
As advice, not an official requirement: make one pass through fluid and construction topics first, since they hold 35 of 50 questions. Give mobilization its own short block for its 9 questions, then finish with timed practice against the one-hour limit. The exam is closed book, so practice recalling definitions and step sequences rather than locating them in a manual.
- Review drilling fluids and well construction topics first — 35 of 50 questions
- Cover site mobilization separately — 9 questions
- Finish with timed, closed-book practice against the one-hour limit
- Track the two-exam 12-month window when scheduling with PSI
Sources: NGWA Certification exams (contractor certification) — Exam categories, preparation materials, and test center information; NGWA DACUM Research Chart: Drilling Contractors and Operators — Duties and task lists for drilling contractors; PSI NGWA candidate information bulletin — Visually checked NGWA content tables, content pages 5–7 (May 2022)
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