PSI is a testing company that delivers plumbing license exams for the state boards that hire it — 20 states use PSI for their plumbing and/or HVAC licensing exams.
The same vendor delivers exams with different rules in different states: Washington's journey-level exam is closed book, Mississippi's plumbing trade exams are open book, and pass marks differ too.
PSI's name alone does not tell you the rules — your board's exam notice is the one to read.
Here is how the PSI-delivered exams work, state by state.
Which states use PSI for plumbing license exams?
Which company delivers a state's plumbing exam is state-specific — it has to be answered from the state files, and our research compiled it that way, board by board, not from any federal source.
Treat the list below as a snapshot with your board as the source of record.
The clearest footprint in that snapshot is PSI's: it delivers state plumbing and/or HVAC licensing exams in 20 states.
The plumbing side is confirmed board by board.
Washington's plumber exams are administered by PSI and sit on the 2015 Uniform Plumbing Code with Washington amendments.
Colorado gives its plumbing exams in English through PSI.
Georgia's construction-board vendor is PSI — confirmed on the plumbing division's own FAQ.
Maryland's State Board of Plumbing exams are PSI-run.
Massachusetts runs its plumbing exams through PSI, Michigan delivers the journey plumber written portion by PSI, and Mississippi's MSBOC administers all of its exams, plumbing trade exams included, through PSI.
New Jersey's master plumber candidates schedule through PSI, and New Mexico's journeyman exams are administered by CID or its designee — PSI.
North Carolina is the clearest logistics example: every exam set by its plumbing, heating and fire sprinkler board is computer-based at PSI Services LLC testing centers in Asheville, Charlotte, Fayetteville, Greenville, Raleigh, Wilmington and Winston-Salem.
Contractor boards hire PSI too.
California's CSLB contracts its contractor exams — law and business plus the C-36 trade exam — to PSI Exams, which delivers them at test centres around the state.
Louisiana's State Licensing Board for Contractors has administered all trade exams through PSI since August 5, 2025.
Ohio's OCILB contractor exams, Nevada's NSCB business and law plus trade exams, the qualifying-party exams South Carolina's CLB requires and Arizona's ROC trade exam all go through PSI as well.
The same state can be both.
Louisiana's contractor board runs its trade exams through PSI, but its journeyman plumber exam is given by the state plumbing board itself, in Baton Rouge and Shreveport — not PSI.
Texas plumbing goes the other way entirely: the TSBPE's written exams are Pearson VUE's, and the board holds its hands-on practical exam at its own Austin or Waco exam centres.
And vendors change — as of July 1, 2026, Prov, not PSI, administers Tennessee's contractor exams, and PSI kept previously scheduled exams through September 2026.
The full vendor map, including the boards that write their own exams, is on our plumbing license exam guide.
Your board's page is the source of record
Scheduling a PSI plumbing exam: board approval first, then PSI
The booking flow runs board-first in the states whose pages state the order: the board qualifies you first, then you schedule with PSI.
Georgia's candidates are approved by the board before they register with PSI.
New Jersey's master plumber candidates schedule the exam through PSI after board approval.
Maryland's candidates upload proof of hours, backflow certification and ID to PSI.
New Mexico's rule wording shows the relationship exactly: the exams are administered by CID or its designee, and the designee is PSI.
The fees can split in two as well: the board's fee and PSI's own exam fee, paid separately.
New Mexico's rule set lists a $25 mechanical journeyman exam fee to CID and a separate PSI exam fee of $68.88.
Massachusetts charges a $31 application fee to the board, and the licence fee — $52 journeyman, $78 master — is paid at the test centre after you pass.
Louisiana's trade exam fees are paid directly to PSI when the qualifying party registers.
Arizona splits the vendors themselves: $61 for the Statutes and Rules exam paid to Gmetrix, $66 for the trade exam paid to PSI.
Your exam's shape lives in its candidate information bulletin: New Mexico's 2023 journeyman plumber bulletin, for one, lays the exam out — 70 questions in 185 minutes, 75% to pass, weighted heaviest on drainage, waste and vents (21 questions), with interceptors and traps and septic and sewer the smallest blocks at 4 questions each.
Practical exams break that pattern where they exist.
Michigan takes one application for both halves of the journey plumber exam — the PSI written and the state's hands-on practical — but the state schedules the practical itself, at sites that fill up.
Texas's TSBPE practical, for one, runs at the board's own Austin or Waco exam centres — not the written exam's vendor.
PSI plumbing exam open-book rules: what PSI's name doesn't tell you
PSI's name on the booking page does not tell you whether you can bring your books.
The same vendor runs both ways: Washington's journey-level and residential plumber exams are closed book, while Mississippi's MSBOC runs all of its exams — plumbing trade exams and the Law and Business Management exam included — open book, through PSI.
Same vendor, opposite rules — so read your own board's notice and the exam bulletin before you count on bringing a book.
Other exam settings vary the same way: Colorado's PSI-delivered plumbing exams pass at 70% for the Residential and Journeyworker exams and 75% for Master.
Exam-day book rules are written per exam, too, and they are not uniform across vendors — Prov's Indiana bulletin, for example, allows highlighting, permanent tabs and handwritten notes only when they are formulas written in ink; moveable tabs, Post-its, photocopied pages and study guides are never allowed.
Read your board's notice before you mark up the code book you plan to sit an exam with.
PSI plumbing exam retakes: the rules come from your board
Retake rules belong to the board, and boards differ.
New Mexico caps the attempts: an exam cannot be repeated more than twice in 30 days, at the 75% pass mark — and its rules-setting board, CID, held an April 2026 hearing on amendments to the exam rules, which is exactly why you check the current rule rather than a forum post.
Massachusetts allows failed plumbing exams to be retaken within 12 months.
Know the bar before you book a second seat.
Colorado passes Residential and Journeyworker candidates at 70% and Master candidates at 75%.
South Carolina's CLB requires 70% on both the technical exam and the S.C. Business Management and Law exam.
New Mexico's journeyman written exam passes at 75%.
What the exam tests, portion by portion, is its own question — our journeyman plumber exam guide covers the written and practical portions, passing scores and prep.
And if you are still mapping the ladder your exam sits on, our plumbing license requirements guide covers apprentice, journeyman and master, state by state.
When the licence lands, plumber jobs are the next stop.
Career information, not legal advice. Exam vendors, fees, open-book rules and retake limits are set by each licensing board and change; confirm yours with your state board — or the city or county where licensing is local — before you book.