The CGWP is one of NGWA's voluntary professional designations, named in NGWA's own designations study guide. Current exam availability, eligibility and content are not established by the retrieved sources, so confirm them with NGWA before planning around a test date. Meanwhile, build reviewable foundations: NGWA's official study guide, USGS-described drilling methods and well development, and specific-capacity practice with its limits understood.
What the CGWP designation is, and what stays unverified
The Certified Groundwater Professional (CGWP) is a voluntary professional designation listed by the National Ground Water Association (NGWA). Current exam availability and requirements are not established by the retrieved sources.
NGWA’s product description for its 2019 Professional Designations Information and Study Guide names CGWP alongside CWD, CPI, CVCLD and MGWC. That confirms the designation’s inclusion in that edition; it does not establish a currently available exam.
What the retrieved pages do not establish is the current route: whether CGWP applications are open today, current eligibility rules, question count, duration, passing standard, or an official content list. Verify those details with NGWA before you book anything or build a schedule around a test date.
Sources checked: NGWA Product Store: Professional Designations Information and Study Guide (downloadable PDF) — Product details and description; NGWA Certification for Contractors — Program overview, eligibility, and contact sections
Contractor certification rules do not transfer to the CGWP
The age, experience, exam-pair and reference requirements NGWA publishes are written for contractor designations. No retrieved source applies them to the CGWP.
NGWA publishes age, experience, required-exam and application rules for its contractor certifications. Those pages do not establish current CGWP requirements. Obtain a CGWP-specific application and eligibility statement before treating any contractor rule as relevant.
Sources checked: NGWA Certification for Contractors — Program overview, eligibility, and contact sections; NGWA Product Store: Professional Designations Information and Study Guide (downloadable PDF) — Product details and description
NGWA's official designations study guide
NGWA’s store describes a 2019 Professional Designations Information and Study Guide that includes CGWP.
The guide lists the skills and competencies for each profession, includes a self-assessment grid to help you build a study plan, and adds glossaries of terms. It also carries test-taking tips, four sample questions per exam, and journal articles on key industry subjects. It replaced NGWA's earlier Voluntary Certification Exam Study Guide.
The product description identifies the edition as 2019. Confirm whether NGWA has current CGWP guidance before buying it for a present-day exam plan. This article uses the public product description; it does not claim to have reviewed the paid guide’s contents.
Sources checked: NGWA Product Store: Professional Designations Information and Study Guide (downloadable PDF) — Product details and description
Drilling methods and well development as review background
USGS Water-Supply Paper 2220 gives stable descriptions of well construction methods and well development that make solid review material, clearly labeled here as background rather than a confirmed CGWP content list.
Basic Ground-Water Hydrology, USGS Water-Supply Paper 2220, describes how each common construction method excavates a well, summarized below. These are descriptive mechanisms for well construction topics. They are not a confirmed CGWP exam blueprint.
USGS distinguishes well development from drilling: development removes clay, silt and fine sand beside the screen or open hole so the well can produce sediment-free water.
| Method | How the hole is made |
|---|---|
| Bored | Earth augers turned by hand or power equipment; described as the modern equivalent of the hand-dug well. |
| Driven | A casing fitted with a screened drive point is driven into place. |
| Jetted | The hole is excavated with a high-pressure jet of water. |
| Percussion (cable tool) | A heavy weight with a chisel bit is alternately raised and dropped; shattered rock and water form a slurry removed with a bailer. |
| Hydraulic rotary (normal) | Rotating drill pipe with a drag or roller bit; drilling fluid with clay circulates down the pipe and up the annular space, cooling the bit and carrying cuttings out. |
| Hydraulic rotary (reverse) | The same rotary principle, but the drilling fluid circulates down the annular space and up the drill pipe. |
| Air rotary | Similar to hydraulic rotary, but the drilling fluid is air rather than mud. |
Sources checked: USGS Water-Supply Paper 2220, Basic Ground-Water Hydrology (1983) — Selected passages on construction methods, well development, and specific capacity
Specific capacity: a calculation you can practice now
Specific capacity is a ratio you can compute from any consistent test pair: pumping rate divided by drawdown, both read at the same elapsed time.
The USGS defines specific capacity as the yield per unit of drawdown, found by dividing the pumping rate at any time during a test by the drawdown at that same time. The same-time condition matters: pairing a rate from one hour with a drawdown from another produces a meaningless number.
Keep the ratio's limits in view as well. Specific capacity describes how much yield each foot of drawdown bought under those test conditions. It cannot, by itself, prove a sustainable long-term rate or justify a pump selection.
Work the practice exercise below, then repeat it with different numbers until the unit pattern is automatic.
Practice exercise
A well is pump-tested at a steady rate of 100 gallons per minute. After 60 minutes of pumping, the water level inside the well has dropped 20 feet below its pre-pumping level. Using the USGS definition of specific capacity, what is this well's specific capacity at that point in the test?
Show answer
5 gallons per minute per foot of drawdown (100 gpm divided by 20 ft equals 5 gpm/ft).
Specific capacity divides the pumping rate by the drawdown measured at the same elapsed time. Here both readings come from the 60-minute mark, so the ratio is valid: 100 divided by 20 gives 5 gpm per foot. The result characterizes this well's yield per foot of drawdown under those test conditions only. It does not, on its own, establish a sustainable long-term pumping rate or justify a pump choice.
Sources checked: USGS Water-Supply Paper 2220, Basic Ground-Water Hydrology (1983) — Selected passages on construction methods, well development, and specific capacity
Preparation priorities and how to verify exam details
Verify the route with NGWA first, then build your plan around its official study guide and groundwater fundamentals that stay useful whatever the requirements say.
Start with the administrative questions, because they decide everything else. Ask NGWA whether CGWP applications and exams are currently offered, what eligibility applies, and which objectives the current exam tests. NGWA lists its certification coordinator at certification@ngwa.org and by phone at (800) 551-7379, or (614) 898-7791 from outside the United States.
While awaiting current CGWP guidance, the background covered here provides a limited starting point: construction-method descriptions, the purpose of well development, and specific-capacity arithmetic. These are not a verified CGWP syllabus.
Sources checked: NGWA Product Store: Professional Designations Information and Study Guide (downloadable PDF) — Product details and description; NGWA Certification for Contractors — Program overview, eligibility, and contact sections; USGS Water-Supply Paper 2220, Basic Ground-Water Hydrology (1983) — Selected passages on construction methods, well development, and specific capacity
Sources checked
Facts checked September 15, 2026: