Two apprentices finish the same program in Cedar Rapids. One is an electrician, the other a plumber. They compare notes over lunch and assume their state exams work the same way. They do not. The electrician books with PSI and needs 70 percent. The plumber books with Kirkwood Community College and needs 75 percent, with a different clock, a different book list and a different retake process.
Here is the plain answer. Iowa’s trade exams are split between two boards and two testing providers. Electrical exams are given by PSI for the Iowa Electrical Examining Board, and the pass mark is 70 percent. Plumbing, HVAC/refrigeration and the other mechanical exams are given by Kirkwood Community College for the Plumbing and Mechanical Systems Board, and the pass mark is 75 percent.
All six exams covered here are open book. They differ in length, time and allowed references, so check yours before you study.
The figures below come from the PSI Iowa electrical candidate bulletin (updated September 19, 2025) and Kirkwood’s State Disciplines exam page, both read today.
The exams at a glance
Electrical (PSI, 70 percent)
- Journeyman Electrician: 80 scored items, 180 minutes. Plus 8 non-scored items with 30 minutes added for them.
- Master Electrician: 100 scored items, 240 minutes. Plus 10 non-scored items with 30 minutes added.
Plumbing and HVAC (Kirkwood, 75 percent)
- Journeyperson Plumber with Gas: 75 questions, 3 hours.
- Master Plumber with Gas: 125 questions, 6 hours.
- Journeyperson HVAC/Refrigeration with Gas: 75 questions, 2 hours.
- Master HVAC/Refrigeration with Gas: 100 questions, 4 hours.
PSI also gives smaller Iowa electrical exams, such as Residential Electrician and Irrigation System Wiring, each with its own count and clock. Kirkwood also covers mechanical, hydronics and sheet metal exams.
Why the pass mark gap matters
Five points sounds small. It changes how you should read your practice scores.
A plumber who scores 72 percent on practice tests has been passing by electrical standards and failing by the standard that actually applies. If you are on the Kirkwood side, set your practice target above 75, not at it. Kirkwood says a score of 75 percent or above is required to pass each exam.
Electrical: the PSI exams
What the journeyman exam covers
PSI publishes the outline as percentages:
- Wiring and Protection: 25 percent.
- Wiring Methods and Materials: 19.
- Equipment for General Use: 19.
- General Electrical Knowledge: 13.
- Special Occupancies: 13.
- Special Equipment and Special Conditions: 6 each.
Wiring and protection alone is a quarter of the exam. That is NEC Chapter 2 territory: branch circuits, feeders, services, overcurrent protection and grounding.
What changes at master
The master exam is 20 more scored items and an extra hour. The weights shift a little, and it adds Communication Systems at 5 percent, which the journeyman outline does not include. Our Iowa Journeyman Electrician exam prep follows the journeyman outline.
The book rules
- Allowed: the 2023 National Electrical Code or the 2023 NEC Handbook.
- Not allowed: Ugly’s Electrical References.
- Tabs: permanent tabs only. PSI defines them as tabs that would tear the page if removed. Sticky notes must come out before the exam starts.
- Marking: highlighting, underlining and indexing are allowed before the exam. Writing in the book is not.
- Calculator: an online calculator is provided, and you may bring a non-programmable one.
- Printouts: a downloaded reference must be bound, spiral or in a binder.
Results
You see your result on screen when you finish. A fail comes with a diagnostic report showing strengths and weaknesses by area. Read it before you rebook.
Plumbing and HVAC: the Kirkwood exams
Journeyperson to master plumber is a big step
The journeyperson plumbing exam is 75 questions in 3 hours. The master exam is 125 questions in 6 hours. That is the biggest jump between consecutive Iowa licenses covered here.
The weights also move. On the journeyperson exam, sanitary drainage and vents are 20 percent each. On the master exam they are 18 each, and isometric drawing appears at 8 percent. Water supply, storm drainage and fuel gas piping carry real weight on both. Allowed references are the 2024 Uniform Plumbing Code and the Iowa State Plumbing Code 2024 amendment booklet. See our Iowa Master Plumber exam prep.
HVAC/refrigeration: watch the short clock
The journeyperson HVAC/refrigeration exam is 75 questions in only 2 hours. That is the tightest pace of the six exams here. Its outline:
- Refrigeration terms, systems and operation: 24 percent.
- Venting, combustion and gas piping: 23.
- Principles, terms, administration and safety: 21.
- Boilers, ducts and electrical: 17.
- Installation requirements: 15.
The master HVAC exam is 100 questions in 4 hours, with refrigeration at 20 percent and venting, duct and combustion air at 18. References for both include Modern Refrigeration and Air Conditioning (21st edition), the 2024 International Mechanical Code and NFPA 54 (2024). Our Iowa Journeyman HVAC exam prep is built to that outline and clock.
Kirkwood’s book and test-day rules
- Any edition: questions are written from a specific edition, but Kirkwood says the references you bring can be any edition. The edition the questions come from is still the safer one to study.
- Format: code references can be bound or loose-leaf.
- Calculator: battery-operated and non-programmable, with no printing or storage.
- Also allowed: an architect’s scale or rule, magnifiers, and translation dictionaries if needed.
- Results: your score shows on screen at the end.
- Retakes: if you do not pass, you register and pay for a new exam.
Getting to the exam, and after it
Electrical: the board approves you first
On the electrical side you do not book PSI directly. The PSI bulletin says you send a license application and a testing sponsorship request to the Electrical Examining Board. Once the board approves it, you get an authorization to test letter, and only then do you pay PSI and schedule.
That letter has limits. It is valid for two exam attempts or six months. If you do not pass in two attempts, you go back to the board for a new authorization before you can test again. The license fee itself is not due until after you pass.
Plumbing and HVAC: Kirkwood books you
Kirkwood registers candidates for the plumbing and mechanical exams. After a pass, Kirkwood says you contact the board office to submit a post-examination licensure application. After a fail, you register and pay for a new exam.
What this means for planning
- Electricians: two attempts per authorization is the real budget. Treat the first attempt as one you intend to pass, not a practice run.
- Plumbers and HVAC techs: every retake is a new registration and a new fee, so the cost of walking in underprepared adds up.
- Everyone: passing the exam is not the license. There is a board step after it on both sides.
How to prepare
- Confirm your provider first. PSI for electrical, Kirkwood for plumbing and mechanical.
- Set your practice target to your real pass mark. Aim above 70 or above 75, depending on the board.
- Practice to your clock. The journeyperson HVAC exam is 75 questions in 2 hours. The master plumbing exam is a 6-hour day.
- Tab the book by the outline. Weight your study time the same way the outline weights the questions.
- On the plumbing side, bring the amendment booklet. Iowa’s amendments are on the reference list next to the UPC.
Questions candidates ask
Is every Iowa trade exam open book?
The six exams covered here are. Kirkwood lists its plumbing and HVAC exams as open book, and PSI’s electrical bulletin allows the 2023 NEC or NEC Handbook.
Do the non-scored electrical questions eat into my time?
No. PSI adds time for them: 30 minutes on both the journeyman and master exams.
Where do these numbers come from?
From the two pages linked at the top. Our page on how we source our exam facts explains how we check them.
Next step
Find your exam on our Iowa exam prep page and practice against the right pass mark from day one.