California C-36 Plumbing Contractor Exam

How to Pass the California C-36 Plumbing Contractor Exam

You don't have to guess how to prepare for the California C-36 Plumbing Contractor exam. This guide lays it out: the key facts from the official bulletin, the topics on the test, the books you need, sample questions with answers, and a study plan you can follow. PSI gives the exam.

California C-36 Plumbing Contractor Exam Basics

Here's what the official bulletin says about the exam:

On exam day

• The examination is multiple choice with four answer choices per question and only one BEST answer.
• One valid, non-expired government-issued photo identification from the listed forms is required before testing, and the name must match the application.
• Candidates must arrive at least 30 minutes before their scheduled appointment time.
• Books, notes and other printed materials other than the materials distributed or otherwise authorized may not be in the candidate's possession during the examination.
• A calculator is provided for the questions that require mathematical computation, while personal calculators are not permitted in the testing room.
• A calculator and in-room timing mechanisms are available, and a long list of personal items—including phones, calculators, textbooks, notes, watches, food and drinks—may not be brought into the testing room.

Scheduling, changes and retakes

• Candidates schedule the examination themselves through PSI, either on PSI's website at https://test-takers.psiexams.com/cacon or by telephone at (877) 392-6422.
• Board approval is required before scheduling, and examination eligibility lasts 18 months from the date the Board deems the candidate eligible.
• An appointment may be cancelled or rescheduled without forfeiting the fee if notice is received two days before the scheduled examination date, through the PSI website or by speaking to a PSI representative.
• Missing the appointment, arriving after the examination start time, failing to cancel two days ahead, or not presenting proper identification causes forfeiture of the examination fee.
• Candidates receive a printed score report at the check-in location immediately after the examination, and scores are not given by telephone.
• Passing candidates receive further instructions by mail from CSLB, because the score report itself is not a license.

Source: Contractors State License Board Licensing Examination Information Guide — Plumbing (C-36). Check the bulletin before test day: fees and rules can change.

What's on the California C-36 Plumbing Contractor Exam

The official content outline splits the exam into 5 topics:

Planning and Estimating: Scope of work and code compliance; Pipe sizing and venting requirements; Shop drawings, plans, and specifications; Job site inspections; Coordination of projects; Water conservation; Cost estimation for materials, equipment, labor, and overhead. Our study plan adds: Fixture unit loading and drainage pipe sizing calculations.
Finish Plumbing Installations: Plumbing fixtures and appliances; Water heaters; Shut-off valves; Specialty installations; Industrial and commercial piping and sanitary systems. Our study plan adds: Water heater seismic strapping and anchorage requirements; Temperature and pressure relief valve installation and discharge piping; Combustion air supply methods for water heaters and fuel-burning appliances.
Service, Repair, and Remodel Plumbing Systems: Troubleshoot plumbing issues; Isolate leaks and damage; Repair plumbing; Retrofit plumbing; Disposal of plumbing materials. Our study plan adds: Water heater permit requirements and inspection procedures; Accessibility compliance requirements during alterations and path of travel upgrades; Asbestos identification and safe work practices during plumbing repair and demolition.

Your California C-36 Plumbing Contractor Study Plan

This one is closed book, so the goal is to walk in knowing the material. Work through the topics in the outline one at a time.

Put your energy where the points are. Planning and Estimating and Underground and Rough Systems make up 44% of the exam, so start there.

Practice with the clock running.

Learn from every miss. Each wrong answer on a practice exam shows you what to review. Read the explanation and the reference until it clicks.

Keep going until you pass practice exams consistently. A few passing scores in a row is how you know you're ready.

Books You'll Need for the California C-36 Plumbing Contractor Exam

CSLB lists these study resources for the C-36 exam. The exam is closed book, so study from them before test day; you can't bring them into the testing room.

• 2025 California Plumbing Code (IAPMO)
• 2025 California Mechanical Code (IAPMO)
• 2025 California Building Code (ICC)
• 2025 California Green Building Standards Code (CALGreen) (ICC)
• California MUTCD, 2014 edition (Caltrans)
• Cal/OSHA General Industry & Electrical Safety Orders and Construction & Electrical Safety Orders (California Code of Regulations, Title 8)
• Underground Service Alert guidelines: California Government Code 4216 and Business and Professions Code 7110

California code books can be viewed online at www.dgs.ca.gov/bsc.

Test Day Tips

Start with a quick pass through the whole exam. Answer every question you're sure about and bookmark the rest. Every exam lets you return to bookmarked questions, so nothing is lost by moving on. One catch: some exams lock the questions you've already seen once you take a break, so clear your bookmarks before any break.

Then come back to your bookmarks and work through them one at a time. Before you finish, make sure every question has an answer. A blank can't earn a point.

Study Tips

Reading the material cover to cover usually isn't enough to pass. This is a multiple-choice exam, and multiple choice rewards practice — the more questions you work through under real conditions, the more the terminology and question style become second nature.

Read the explanation for every question — right or wrong. Understanding the underlying rule lets you answer reworded questions you've never seen, instead of memorizing specific answers.

Several 25–30 minute sessions across the week beat one long cram. Spaced repetition moves facts into long-term memory so they stick through exam day.

Practicing against a ticking clock is the best way to beat exam-clock anxiety. Use these timed tests to build your pacing, so you learn to move steadily and never burn too long on a single question. By test day, the format feels routine.

Try These California C-36 Plumbing Contractor Practice Questions

Give these a try. They come from our practice question bank, each with its answer and reference.

Sample 1 — Service, Repair, and Remodel Plumbing Systems

Question: A customer complains of noisy, whistling hot water lines in a copper tube system, and you are resizing the hot water distribution piping during the remodel. For copper and copper alloy tube and fitting systems, the code limits velocity in hot water to a maximum of:

• A. 5 feet per second
• B. 12 feet per second
• C. 10 feet per second
• D. 8 feet per second

Correct Answer: A

Per CPC Section 610.12.1, maximum velocities in copper and copper alloy tube and fitting systems shall not exceed 8 ft/s in cold water and 5 ft/s in hot water. The lower hot-water limit reduces erosion-corrosion and noise.

Reference: 2025 California Plumbing Code, Section 610.12.1

Sample 2 — Safety

Question: Before digging a new lateral, you call the one-call notification center and the utility owners mark the site. Under the uniform color code, sewer and drain lines are marked with which color?

• A. Purple
• B. Green
• C. Blue
• D. Orange

Correct Answer: B

The uniform color code marks sewers and drain lines green. Blue indicates potable water, orange indicates communication/alarm/signal lines, and purple indicates reclaimed water, irrigation, and slurry lines.

Reference: Plumbing Basics for Contractors (4th ed.), Module 02102, Section 4.1.5 (One-Call Notification, APWA color code)

Sample 3 — Planning and Estimating

Question: You are pricing the vent piping for a floor drain served by a 3 inch fixture drain. Applying the minimum sizing rule for an individual vent, the smallest vent pipe you may install is ___ inches.

• A. 3
• B. 1-1/4
• C. 1-1/2
• D. 2

Correct Answer: C

The diameter of an individual vent shall be not less than 1-1/4 inches nor less than one-half the diameter of the drain to which it is connected. One-half of a 3 inch drain is 1-1/2 inches, which governs over the 1-1/4 inch absolute minimum.

Reference: 2025 California Plumbing Code, Table 703.2, Note 6

Sample 4 — Underground and Rough Systems

Question: As the plumbing contractor on a building served by both potable and nonpotable water systems, you are field-marking the exposed nonpotable piping with the required yellow background and black uppercase lettering. How often must the background color and required information be repeated along the run?

• A. Every 15 feet, but not less than once per floor
• B. Every 20 feet, but not less than once per room
• C. Every 10 feet, but not less than once per room
• D. Every 25 feet, but not less than once per floor

Correct Answer: B

Per CPC Section 601.3.2, the background color and required information for nonpotable water systems shall be indicated every 20 feet (6096 mm) but not less than once per room, and shall be visible from floor level. The other intervals and the 'per floor' qualifiers are not code requirements.

Reference: 2025 California Plumbing Code, Section 601.3.2

Why Practice Online?

Reading questions in a PDF is a start, but it doesn't prepare you for the clock. Our practice exams are timed and on a screen, so you build speed along with knowledge. Each attempt draws a new set of questions from our bank, and your results show your score by topic so you know where to focus next.

Ready to Start?

Take the free California C-36 Plumbing Contractor practice exam and see where you stand today. Then focus on the topics that need the most work. For the official rules, read the exam bulletin, and see the licensing board's website.