South Carolina Residential Plumbing

SC Residential Plumbing License Exam: Complete 2026 Study Guide

You've put in the work on job sites. Now you need to prove it on paper. The SC Residential Plumbing License exam is a 65-question, open-book test administered by PSI — and passing it is the key step toward getting your residential contractor license in South Carolina. This guide covers exactly what's on the exam, what books to bring, and how to prepare efficiently.

Want to see what the questions feel like right now? Try our free practice exam — no account required.

Exam Overview

Format at a glance:
- Questions: 65 scored questions
- Time: 180 minutes (3 hours)
- Passing score: 45 out of 65 correct (68%)
- Delivery: Computer-based at a PSI test center
- Open book: Yes — approved references allowed

The exam covers eight topic areas, from DWV system design to safety regulations. You'll have just under three minutes per question on average, which is comfortable — the bigger challenge is finding answers in your reference books quickly when you need them.

Before you can register, you must apply through the South Carolina Residential Builders Commission and receive an Examination Eligibility letter. Once eligible, register through the exam registration page online (available 24/7) or call PSI at (855) 340-3701. Check the official exam bulletin and the state licensing website for current application requirements.

Topics Covered on the Exam

Here's how the 65 questions break down by topic area:

Where to focus first: DWV and General Plumbing together account for 32 of the 65 questions — nearly half the exam. Get those right and you're most of the way to passing. Isometric drawing interpretation is the third-largest category at 9 questions and is a skill many test-takers underestimate.

Sample Residential Plumbing Exam Questions

Here are five real-style questions from the exam. See if you can work them out — but check the free practice exam to find out how you actually scored.

Question 1 — Specialty Applications

Point-of-use reverse osmosis drinking water treatment units must comply with which of the following standards?
- A) CSA B483.1 or NSF 58
- B) ASSE 1012 or CSA B64.3
- C) NSF 61 or NSF 42
- D) ASSE 1024 or CSA B64.6

This tests your knowledge of water treatment equipment standards — you'll need to know which standard applies to which device type.

Question 2 — General Plumbing Knowledge and Regulations

When making CPVC water supply piping solvent cement joints using the standard two-step method, what color must the solvent cement be and to what standard must it conform?
- A) Orange, conforming to ASTM F493
- B) Yellow, conforming to ASTM D2564
- C) Purple, conforming to ASTM F656
- D) Clear, conforming to ASTM D2235

A detail-oriented question — the code specifies both the color and the ASTM standard, and you need both right.

Question 3 — Specialty Applications

A sediment trap installed downstream of the appliance shutoff valve shall consist of a tee fitting with a capped nipple installed vertically in the ______ opening of the tee.
- A) topmost
- B) bottommost
- C) horizontal
- D) upstream

Gas appliance installation specifics show up in Specialty Applications. Know your trap configurations.

Question 4 — Drain, Waste and Vent and Sewers

When installing a circuit vent system on a horizontal branch drain, what is the maximum number of fixtures that may be circuit vented?
- A) Four
- B) Ten
- C) Eight
- D) Six

DWV is the largest topic on the exam. Circuit vent rules, fixture counts, and sizing come up repeatedly.

Question 5 — Water Supply

The developed length of hot or tempered water piping from the source of hot water to the fixtures requiring hot or tempered water shall not exceed ______ feet.
- A) 25
- B) 100
- C) 50
- D) 75

Hot water distribution limits are a classic code-lookup question. Tab this section in your IRC.

What Types of Questions to Expect

Our full practice exam bank has 362 questions across all eight topics. Here's what each area tests:

• General Plumbing Knowledge and Regulations — 63 practice questions: Material standards, solvent cement specifications, faucet repair procedures, pressure head calculations, and pipe joining techniques (soldering and solvent welding). Expect to calculate area and volume.
• Piping, Valves, and Controls — 40 practice questions: Installation methods for PVC, CPVC, galvanized, and copper piping and tubing. Includes fitting selection, connection requirements, and material-specific rules.
• Fixtures and Equipment — 26 practice questions: Minimum fixture counts by occupancy type, clearance requirements, and installation procedures for specific fixtures.
• Water Supply — 58 practice questions: Distribution system design, pressure and flow rate criteria, fixture unit loads, backflow prevention device types and applications, and cross-connection control requirements.
• Drain, Waste and Vent and Sewers — 86 practice questions: The largest section by far. Covers DWV system design, building sewer installation, cleanout placement, trap requirements, sewage ejectors, sump pumps, and venting configurations including circuit vents.
• Isometric Analysis — 31 practice questions: Reading and interpreting isometric plumbing drawings to identify pipe runs, fittings, and system configurations. This is a skill-based section — practice matters.
• Safety — 22 practice questions: OSHA requirements for PPE, trench and excavation safety, ventilation requirements, and required safety training.
• Specialty Applications — 36 practice questions: Backflow preventer installation, water heater installation and repair (electric, gas, and tankless), gas appliance connections, and water filtration and conditioning systems.

Required Reference Books and Study Materials

The SC Residential Plumbing exam is open book. You must bring your own references — the test center does not provide them.

Required references:
- South Carolina International Residential Code for One- and Two-Family Dwellings / IRC 2018 — your primary residential code reference. Tab it heavily.
- OSHA 29 CFR 1926 — required for the Safety topic and any safety-related questions throughout the exam.
- South Carolina International Plumbing Code / International Plumbing Code (2021 edition) — check the official exam bulletin for the current approved edition.

Note: The 2021 IPC is listed as an approved reference in the bulletin. Confirm the current approved edition before purchasing.

Study supplies that make a real difference:

An open-book exam rewards fast lookup. Sharpie Highlighters — these come in a 12-pack with multiple fluorescent colors — let you color-code by topic so you can find DWV rules, water supply tables, and safety standards in seconds. Pair them with Redi-Tag Permanent Colored Tabs to flag key code sections. Permanent tabs stay put through repeated use; you get 100 in 5 colors, which is more than enough to index all three books by topic.

A well-tabbed, highlighted code book is worth more than hours of extra reading.

Study Tips for the SC Residential Plumbing Exam

Use elimination on tough questions. Rule out the options you know are wrong before choosing. Getting down to two choices cuts your odds of guessing wrong in half, even when you're not sure of the answer.

Study in short, regular sessions. Several 25–30 minute sessions spread across a week beat a single long cram. Spaced repetition moves code details into long-term memory so they're accessible under test pressure.

Read every explanation. Whether you got the question right or wrong, read the explanation. Understanding the underlying code rule — not just the answer — lets you handle reworded questions you've never seen before.

Tab before you study. Set up your code books before you start practicing. Use your color tabs to mark DWV, water supply, fixture requirements, and safety sections. On exam day, you want your hands to find the right page almost automatically.

Prioritize by weight. DWV (17 questions) and General Plumbing (15 questions) together make up nearly half the exam. Spend proportionally more time there before moving to smaller topics.

Frequently Asked Questions

How many questions are on the South Carolina Residential Plumbing exam and how long do I have?
The exam has 65 scored questions and you have 180 minutes (3 hours) to complete it.

What is the passing score for the SC Residential Plumbing exam?
You need 45 out of 65 correct to pass (68%). Note that this passing score may be adjusted as PSI evaluates exam performance over time.

How much does the exam cost?
The bulletin lists $90 for both exam portions or $75 for one portion, but doesn't break out the Residential Plumbing fee separately. Call PSI at (855) 340-3701 to confirm the exact fee for your situation.

Is the SC Residential Plumbing exam open book?
Yes. You may bring the approved reference books, which may be highlighted, underlined, and tabbed with permanent index tabs — but must not contain handwritten notes or loose papers.

What reference books can I bring?
The three approved references are: the SC IPC or IPC (2021 edition), the SC IRC or IRC (2018 edition), and OSHA 29 CFR Part 1926 with latest amendments. You must bring your own copies — none are provided at the test center.

Do I need to pass another exam besides Residential Plumbing?
Yes. All candidates must also pass the Business Management and Law for Residential Builders exam. Both exams must be passed within the same 12-month eligibility period.

How many attempts do I get?
Three attempts within a 12-month eligibility window. If you fail three times, you must wait 12 months from your last attempt before testing again.

How do I register?
Apply first through the SC Residential Builders Commission. Once you receive your eligibility letter, register at the exam registration page or call PSI at (855) 340-3701.

What ID do I need?
One valid, non-expired, signature-bearing photo ID. Acceptable forms include a state driver's license, state ID card, U.S. passport, U.S. military ID, Alien Registration Card, or Canadian government-issued ID. The name must match your registration.

Can I use a calculator?
Yes — a silent, battery-operated, non-printing, non-programmable calculator with no alphabetic keyboard is permitted.

Start Practicing Today

The SC Residential Plumbing License exam is achievable with the right preparation. You know the trade — now build your code knowledge to match.

Start with our free practice exam to get a feel for the residential plumbing exam questions and format. When you're ready to prep seriously, upgrade to the full practice exam: 65 questions, same time limit, same topic breakdown as the real test, with a detailed score report showing exactly where you need more work.

Get your books tabbed, start practicing, and go get that license.