NGWA Exam K: Water Systems Less Than 100 GPM is a closed-book, specialized exam of 50 questions taken in one hour, with a 70 percent minimum passing score. Its questions fall into four areas: Assess Job Site (1 question), Determine System Component Requirements (19), Install Pump System (9), and Troubleshoot Existing Pump System (21). Passing it is one step toward the Certified Pump Installer designation, which also requires the Water Systems General exam, both passed within one 12-month period.
What Exam K covers, and the numbers to expect
Exam K tests water systems that pump less than 100 gallons per minute. You answer 50 questions in one hour, closed book, and need at least 70 percent to pass.
PSI’s September 2022 bulletin lists four areas. Component requirements and troubleshooting together account for 40 of 50 questions; assessment and installation account for the remaining ten. Use the distribution and your own knowledge gaps to plan revision.
The companion exam, Exam L, covers water systems greater than 100 GPM. The retrieved documents list Exam K as less than 100 GPM and Exam L as greater than 100 GPM, and they do not assign a system of exactly 100 GPM to either one. If your work sits on that boundary, confirm placement with NGWA before you register.
| Content area | Questions |
|---|---|
| Assess Job Site | 1 |
| Determine System Component Requirements | 19 |
| Install Pump System | 9 |
| Troubleshoot Existing Pump System | 21 |
Official sources: Groundwater | NGWA Certification exams — Certification exams section; PSI NGWA candidate information bulletin — Visually checked NGWA content tables, pages 5-7
How Exam K fits the Certified Pump Installer designation
Exam K alone does not certify you. The CPI designation requires the Water Systems General exam plus at least one specialized pump or water systems exam, both passed within 12 months.
To earn the Certified Pump Installer designation, you must pass the Water Systems General exam and one other specialized pump or water systems exam, which for most small-system installers means Exam K or Exam L. You must pass both required exams within one 12-month period, scoring 70 percent or better on each. Exam N, well servicing and maintenance, is a separate specialty exam, not one of the two qualifying exams for the CPI path.
Certification eligibility goes beyond the exams. NGWA requires that you be at least 20 years old, have at least 24 consecutive months of full-time drilling or pump installation experience, and submit written references from two professional contacts unaffiliated with your current company, plus an agreement form and a current-year affidavit. Application materials must arrive within 12 months of your qualifying exam session.
Keep certification and licensing distinct in your planning. The NGWA program, running since 1970, is a voluntary national certification that many state agencies have adopted for their own licensing programs. Which exams your state requires, and under what rules, is controlled by current state regulations, not by NGWA's pages.
Official sources: Groundwater | NGWA Certification exams — Certification exams section; Groundwater | NGWA Certification for contractors — Eligibility section
Determine System Component Requirements: 19 questions on selection decisions
This is one of the two heavyweight areas. It tests whether you can size and select system components from source conditions and test data, the way a working installer chooses a pump, pipe, wire, and tank for a specific well.
NGWA's job task analysis chart for pump installers shows what this area draws on. Before selecting anything, an installer determines water source parameters and evaluates pump test results; then come the selection decisions themselves: pump type and size, pipe type and size, wire type and size, the pressure or water storage tank and its mechanical and electrical components, and the type of wellhead completion. Practicing the sequence, source data first, then component choices, mirrors how the job and the exam area are organized.
USGS defines specific capacity as pumping rate divided by drawdown measured at the same time. It expresses water yield per foot of drawdown at that observation. The original exercise below uses that definition without treating it as a complete pump-selection calculation.
Practice exercise
During a pumping test on a small well, the pump delivers a sustained 12 gallons per minute, and at that same moment the water level inside the well stands 4 feet below its pre-pumping level. Calculate the well's specific capacity, and name one conclusion this single figure cannot support.
Show answer
Specific capacity is 12 divided by 4, which equals 3 gallons per minute per foot of drawdown. This figure alone cannot prove the well can sustain a household's long-term water demand.
Both readings are taken at the same moment: 12 gpm divided by 4 ft is 3 gpm/ft. This ratio describes the supplied observations. It does not by itself establish long-term household supply.
Official sources: PSI NGWA candidate information bulletin — Visually checked NGWA content tables, pages 5-7; DACUM Research Chart for Pump Installers — Duties A-G; USGS Water-Supply Paper 2220, Basic Ground-Water Hydrology — Selected fundamentals, printed pages 52-53 and 58
Troubleshoot Existing Pump System: 21 questions, the largest area
Troubleshooting has 21 of 50 questions. Use the pump task chart to identify the subjects to review: controls, electrical parameters, pump operation and water-source conditions.
The chart lists observing the system and surrounding area, checking controls, checking electrical parameters such as volts, amps and resistance, checking operation such as pressure, cycle time and flow, and checking water-source parameters. These are task categories, not a diagnostic procedure or an instruction to perform live electrical measurements.
For revision, explain which kind of information each task concerns. Use the recommended technical references for procedures and equipment-specific interpretation. The task chart does not establish one universal order that solves every fault.
Official sources: PSI NGWA candidate information bulletin — Visually checked NGWA content tables, pages 5-7; DACUM Research Chart for Pump Installers — Duties A-G
Assess Job Site and Install Pump System: the two smaller areas
Assessment (1 question) and installation (9 questions) are smaller, but they close the loop on the full job: judging the site before work begins and completing the installation to a working, sampled system.
Site assessment covers accessibility, safety concerns, water-source location, space for equipment, utilities, plumbing and regulatory requirements. Its one-question allocation does not establish that a brief checklist is sufficient preparation.
Installation topics in the chart range from equipment preparation through pump and component installation, system testing, water sampling and field documentation. Review these topics in the recommended references; the chart does not provide the detailed methods or settings.
Official sources: PSI NGWA candidate information bulletin — Visually checked NGWA content tables, pages 5-7; DACUM Research Chart for Pump Installers — Duties A-G
How to prepare and book your exam
Study from NGWA's recommended water systems texts and the pump installer task chart, then schedule through PSI, which administers the exam year-round at more than 400 test centers for 75 dollars per exam.
For the water systems exams, NGWA recommends the Water Systems Handbook, 13th edition; Engineering Your Business; and Basic Water Systems: A Pump and Hydraulic Training Manual, along with the Professional Designations Information and Study Guide for all exams. NGWA University also offers self-paced online training for the general and water systems exams, built with NGWA-approved subject matter experts.
Use the pump installer DACUM chart as a free map of the job the exam draws from. Reading duties A through G and asking whether you could explain each task is a faster coverage check than rereading chapters at random. Note that the chart's duty letters are job-duty labels, not exam codes, so duty C on the chart has no special connection to Exam K.
Logistics are straightforward. Each exam costs 75 dollars regardless of NGWA membership. You schedule through PSI's website or by phone, sit the closed-book exam at a test center, and receive your score immediately; collect the printed score report before leaving, because scores are not issued over the phone and reissues carry a fee. If you sit both the general and specialized exams, track your own 12-month window. One detail the retrieved sources do not specify is the question format, so check NGWA's Exam Preparation Success Guide or ask certification staff if format matters to your preparation.
- Read the pump installer DACUM chart and confirm you can explain each duty and task
- Work specific-capacity and source-data interpretation examples until the arithmetic is routine
- Review the separate troubleshooting tasks for controls, electrical parameters, pump operation and water-source conditions
- Schedule early enough to pass both required exams within one 12-month period
- Confirm your state's licensing requirements separately from NGWA certification
Official sources: Groundwater | NGWA Certification exams — Certification exams section; PSI NGWA candidate information bulletin — Visually checked NGWA content tables, pages 5-7; DACUM Research Chart for Pump Installers — Duties A-G; USGS Water-Supply Paper 2220, Basic Ground-Water Hydrology — Selected fundamentals, printed pages 52-53 and 58
Official sources
Facts checked against official sources: