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ICC E1, M1 and P1: the residential trade inspector exams

Rafter Tie editorial teamUpdated 8 min read

E1, M1 and P1 are ICC's three residential trade inspector exams: E1 Residential Electrical Inspector, M1 Residential Mechanical Inspector and P1 Residential Plumbing Inspector. Pass all three and hold the B1 Residential Building Inspector certification, and ICC grants the R5 Residential Combination Inspector designation. Each one is a 60-question, 2-hour exam with a $320 list price. This page puts the three side by side, shows what each covers and which books to bring, and explains why the B1 usually comes first.

What E1, M1 and P1 are

Each exam certifies one trade on one- and two-family homes:

  • E1 Residential Electrical Inspector. ICC's outline scopes it to electrical systems indoors and outdoors on one- and two-family dwellings, limited to 120/240 volt single-phase services up to 400 amps.
  • M1 Residential Mechanical Inspector. Heating, cooling, ventilation, ducts, chimneys and vents, and fuel supply on residential work.
  • P1 Residential Plumbing Inspector. The whole residential plumbing system, from water supply to drainage and vents. ICC's outline also puts fuel gas piping, combustion air and venting for water heaters in scope.

They sit in the same "Residential Inspector" group on ICC's national exam list as the B1. ICC's combination designations page lists B1, E1, M1 and P1 as the four certifications behind R5. The B1, B2 or R5 comparison shows where R5 sits next to the commercial exams.

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The three exams side by side

E1M1P1
ICC titleResidential Electrical InspectorResidential Mechanical InspectorResidential Plumbing Inspector
Questions606060
Time2 hours2 hours2 hours
Open bookYes, per the E1 outlineCheck the catalog listingYes, per the P1 outline
Code years offered2021 and 20242021 and 20242021 and 2024
Books named by the 2024 study guide2024 IRC and 2023 NEC2024 IRC2024 IRC
List price$320$320$320

Questions, time and price come from each exam's ICC store listing. The E1 outline and P1 outline both describe 60 multiple-choice questions, a 2-hour limit and an open-book exam. The M1 outline ICC posts online is marked for exams built before July 2015, so this page takes the M1 format from the store listing and leaves its open-book status to the exam catalog. Code years are from ICC's national exams list.

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What the E1 covers

The E1 outline splits the exam into six areas:

E1 content areaWeight
General requirements10%
Services17%
Branch circuit and feeder requirements28%
Wiring methods and power and lighting distribution21%
Devices, lighting fixtures and appliances19%
Swimming pools and similar installations5%

Branch circuits, feeders and wiring methods make up almost half the exam. That block covers feeder and branch circuit sizing and load calculations, overcurrent protection, required circuits, panelboards, required outlets, GFCI locations, boxes and equipment grounding. Services, at 17%, splits between service size and rating and service grounding and bonding. General requirements include a small slice of electrical theory, working clearances, splices and conductor types. Pools, spas and hot tubs close the outline at 5%.

What the M1 and P1 cover

M1. ICC's 2024 M1 study guide works through seven topics: general administration; heating, cooling and water heaters; exhaust and ventilation systems; duct systems; combustion air; chimneys and vents; and fuel supply systems. ICC does not post a current weighted M1 outline that we could read, so this page gives no M1 weights.

P1. The P1 outline uses six weighted areas:

P1 content areaWeight
General requirements14%
Fixtures8%
Water heaters12%
Water supply and distribution21%
Sanitary drainage23%
Vents22%

Drainage, vents and water supply carry 66% of the P1. Vents alone are 22%, with half of that on venting requirements, methods and installation, so vent sizing and layout deserve real study time. General requirements cover permits, protecting and installing piping, damage to building components and testing.

Two areas overlap between the exams. Water heaters appear on both the M1 and the P1, and fuel gas shows up in M1's fuel supply topic and in P1's water heater area. Study either one and you start the other with part of the ground covered.

Which code books each uses

ICC's 2024 study guides name the books for the 2024 code year:

So one IRC carries you through the B1, M1 and P1, and the E1 adds the NEC. If you book the 2021 code year, check the references on that exam's catalog listing before you buy books, and keep the exam and the book on the same edition. The 2021 or 2024 IRC guide helps you pick.

Cost and booking

Each of the three ICC store listings shows a $320 list price, the same as the B1. The E1, M1 and P1 listings each say purchases are valid for 365 days, and each sells the exam in the PRONTO format with a choice of the 2021 or 2024 code cycle. ICC members see a member price.

At list price that is $960 for the three trade exams, or $1,280 for all four R5 exams with the B1, before books, retakes or a test-center premium. The ICC exam cost and scheduling guide walks through booking in PRONTO, choosing remote proctoring or a test center, and the premium for testing in person. ICC charges the exam fee again at every attempt; the results and retakes guide covers the score report and ICC's attempt limits.

Building to R5: why the B1 is the usual first step

ICC grants R5 automatically once you hold all four residential certifications. Its designations page lists them with no required order, so the order is yours to choose. The B1 is the usual first step, for three reasons:

  1. State rules name it. The Kentucky, Rhode Island and New Jersey rules in our B1, B2 or R5 comparison all name the B1 for their residential level. Kentucky's one- and two-family dwelling inspector and New Jersey's RCS level pair it with the M1.
  2. The book carries forward. The IRC you tab for the B1 is the main reference for the M1 and P1 too, and a reference for the E1.
  3. It opens the most doors. The B1 is a step toward R5, B5 and C8 on ICC's designations page.

Two rules from that same page matter once you get there. ICC does not treat older model-code inspector certifications as equivalent to the four ICC residential certifications, and renewing the individual certifications does not automatically renew the R5 designation. ICC's renewal page says certifications are valid for three years and are renewed with continuing education units.

Not sure which exam to start with? The ICC exam picker takes what you inspect, what you hold and your state, and shows the next exam.

Start with the B1: take the free check

Rafter Tie prepares you for the B1, the usual first step of the four R5 exams. Take the free 10-question check to see your score by B1 outline area in minutes, with no signup. Every answer is explained. The Rafter Tie course adds timed practice exams, a lesson for each area and a study plan built from your exam date.

FAQ

Is there a free ICC E1 practice test?

Rafter Tie's free 10-question check is for the B1, not the E1. If you are building toward R5, the B1 is the usual first exam, and the check scores you by B1 outline area. For the E1 itself, ICC sells a 2024 E1 study guide, and the E1 outline weights above show where to spend your time.

How many questions are on the ICC E1, M1 and P1 exams?

Each ICC store listing shows 60 questions and 2 hours, and each exam costs $320 at list price.

Are the E1, M1 and P1 open book?

The E1 and P1 outlines both say open book. The M1 outline ICC posts online predates July 2015, so check the references on the M1 catalog listing before exam day.

Which order should I take the R5 exams in?

ICC's designations page lists B1, E1, M1 and P1 with no required order. Starting with the B1 makes sense because state rules name it and its IRC carries over to the M1 and P1. If your state pairs the B1 with the M1, as Kentucky and New Jersey do, take the M1 next.

How long does ICC certification last?

ICC says certifications are valid for three years, and you renew them with continuing education units earned in that period. Renewing the four individual certifications does not automatically renew the R5 designation.

What books do I need for the E1?

ICC's 2024 E1 study guide lists the 2024 IRC and the 2023 NFPA National Electrical Code. The M1 and P1 study guides list the 2024 IRC alone.

Sources

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