Plumbing licence exams are built on code books, and the boards behind them do not all name the same one: Montana's journeyman written exam is based on the 2021 Uniform Plumbing Code (UPC) as amended, while Alabama's PGFB exams have tested the 2021 International Plumbing Code (IPC) or the 2021 International Fuel Gas Code since January 1, 2023.
Here is what each state's licensing record in our research names, and what that means for your exam.
Differences that matter on the exam
There is no single code book under every plumbing licence exam.
Some boards test the Uniform Plumbing Code (UPC), others the International Plumbing Code (IPC), and a state can base its own code on one of them — Minnesota's 2020 plumbing code is based on the 2018 UPC with Minnesota amendments.
The choice decides which book holds the answers your exam is keyed to — so the family, the edition and the amendments all matter.
One example of how specific the books get, from the IPC side: under the 2024 International Plumbing Code, Table 704.1 sets the minimum slope for horizontal drainage pipe at 1/4 inch per foot for pipe 2-1/2 inches or smaller, 1/8 inch per foot for 3- to 6-inch pipe, and 1/16 inch per foot for 8-inch and larger — and the same table requires at least 1/4 inch per foot (2 percent) for drainage piping upstream of a grease interceptor, whatever the pipe size.
Our research did not check the UPC's own slope values, so we won't compare the two tables here; the working point is that the answer lives in the edition your board adopted.
Edition matters alongside family.
Indiana's plumbing exams still reference the 2006 International Plumbing Code (Indiana edition) with 2012 Indiana amendments, per the Prov bulletin dated May 2026 — practice questions written for the 2021 or 2024 IPC can misalign there.
Nevada recertifies NBOPE certificates expiring after January 1, 2019 to the 2024 UPC, Montana's journeyman and master exams run on the 2021 UPC as amended, Alaska's journeyman exam on the 2018 edition.
"UPC or IPC" is really three variables: which family, which edition, which amendments.
For the exam wrapper around the book — who administers it, open-book rules, retakes and wait times — see our plumbing license exam guide.
Match any practice sets to your state's code and edition before you drill; our journeyman plumber practice test article splits practice questions by UPC and IPC.
Codes and editions change — confirm yours
Which states use the UPC, and which use the IPC?
First, the honest limit of this page: our research found no primary source that maintains a complete UPC-vs-IPC adoption map, so this page is not that table.
What follows is the states whose licensing records our research covers with a named code — the exam outlines, code adoptions and continuing-education rules their boards publish.
A state missing below means our research has not pinned its code, not that it has none; your board's exam notice is the source of record.
On the UPC side — records that name the UPC or an IAPMO Uniform-code edition:
| State | What the licensing record says |
|---|---|
| Alaska | Adopts the 2018 Uniform Plumbing Code (IAPMO) under 8 AAC 63.101; the Plumber Journeyman exam is open book on the 2018 UPC. |
| Hawaii | The plumber exam is based on the Uniform Plumbing Code and administered by Prometric; the Journey Worker Plumber licence requires 5 years and at least 10,000 hours of plumbing work under the UPC. |
| Minnesota | The 2020 Minnesota Plumbing Code (chapter 4714), effective December 17, 2021, is based on the 2018 UPC with Minnesota amendments. |
| Montana | The journeyman written exam runs on the 2021 UPC (as amended); the master exam on the 2021 UPC as amended — candidates bring their own tabbed code book. |
| Nevada | The NBOPE journeyman and master exam is based on the currently adopted UPC; recertifications for certificates expiring after January 1, 2019 are to the 2024 UPC. |
| New Mexico | The journeyman plumbing exam's references include the 2021 Uniform Plumbing Code (IAPMO). |
| South Dakota | The plumbing code standard is the 2024 Uniform Plumbing Code (IAPMO), as adopted by the commission. |
| Washington | Plumber exams administered by PSI are based on the 2015 UPC with Washington amendments. |
| California, Idaho | IAPMO publishes state-specific editions of its Uniform codes for their plumbing codes. |
On the IPC side — records that name the IPC or an ICC-published state edition:
| State | What the licensing record says |
|---|---|
| Alabama | Since January 1, 2023, Alabama PGFB exams test the 2021 International Plumbing Code or the 2021 International Fuel Gas Code. |
| Arkansas | The state's Plumbing and Fuel Gas Codes are state editions published by the International Code Council (ICC); the edition year is not stated in the materials our research read. |
| Colorado | In June 2026 the State Plumbing Board held a rulemaking hearing to adopt new editions of the International Plumbing Code, Fuel Gas Code and International Residential Code (edition numbers not stated). |
| District of Columbia | Plumbing and gas exams are open book, referencing the 2012 International Plumbing Code and the 2012 International Fuel Gas Code. |
| Indiana | Exams still reference the 2006 IPC (Indiana edition) with 2012 Indiana amendments, per the Prov bulletin dated May 2026. |
| Louisiana | The Journeyman Plumber exam is an 80-question, 3-hour written exam on the 2021 IPC and the 2021 International Residential Code, plus a 1-hour practical. |
| Vermont | Adopts the 2021 International Plumbing Code, with the Vermont Plumbing Rules (2025 edition). |
| Virginia | Plumbing continuing education must cover the International Plumbing Code. |
Two wrinkles keep the map honest.
The code that applies can be set locally: outside city limits in Nebraska, sanitary plumbing in buildings other than single-family homes and farm/ranch structures needs a permit from the nearest city or village, and the 2018 Uniform Plumbing Code applies where that city has no plumbing ordinance of its own.
And cities can carry their own editions — IAPMO's state-adopted-codes list includes city codes for Seattle and Houston.
The book you studied and the book a job site is inspected against are not automatically the same document.
Where the code sits in the bigger picture — the apprentice, journeyman and master rungs it tests into — is its own question: our plumbing license requirements guide covers the ladder, and the state pages in that series carry each state's own licensing detail.
What it means when you move states
Whether your experience and licence carry across a state line is a reciprocity question — see plumbing license reciprocity for how the agreements work and what actually transfers.
The code book is a separate one: the exam you sit in a new state — if that state makes you sit one — is built on the code book that state's board names, so a plumber moving from a UPC state to an IPC state is studying a different book, not learning the trade again.
Boards can tie qualifying experience to the code itself.
Hawaii's Journey Worker Plumber licence, for example, requires 5 years and at least 10,000 hours of plumbing work under the Uniform Plumbing Code — a question for the Hawaii board if your hours were logged under a different code.
The code keeps following you after licensure, through continuing education.
Alaska requires 16 hours of CE in the prior 24 months to renew a journeyman certificate, at least 8 of them on changes to the UPC.
Virginia's plumbing CE must cover the International Plumbing Code.
Hawaii expects a course on Uniform Plumbing Code updates at renewal.
Which code book your CE hours track depends on which state licenses you.
The practical sequence when a move is coming: ask the new board which code and edition its exam tests, get that book, and match your practice questions to it — then check whether reciprocity waives the exam altogether.
The trade is the same trade everywhere; the reference book is not.
This page is career information, not legal advice — confirm the code, edition and exam your board requires with your state licensing board, or the city or county where licensing is local.