100+ Free NC Plumbing Contractor Practice Questions

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Question 1

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Under the IPC adopted by North Carolina, what is the minimum slope for a 4-inch horizontal drain?

1/16 inch per foot

1/8 inch per foot

1/4 inch per foot

1/2 inch per foot

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Key Facts: NC Plumbing Contractor Exam

70%

Passing Score

NC Board of Examiners

~100

Questions

PSI exam

$125

Total Cost

$25 exam + $100 license

NC SPC

Code

Based on IPC

The NC plumbing contractor exam has approximately 100 questions requiring 70% to pass. NC uses the NC State Plumbing Code based on the IPC. The exam is administered by PSI with a $25 exam fee and $100 license fee. NC is one of few states with a contractor-level exam rather than journeyman.

Sample NC Plumbing Contractor Practice Questions

Try these sample questions to test your NC Plumbing Contractor exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Under the IPC adopted by North Carolina, what is the minimum slope for a 4-inch horizontal drain?

A.1/16 inch per foot

B.1/8 inch per foot

C.1/4 inch per foot

D.1/2 inch per foot

Explanation: Under the IPC, 4-inch and larger drains require 1/8 inch per foot minimum slope. Pipes 2-1/2 inches and smaller require 1/4 inch per foot. North Carolina enforces IPC standards via NC Board of Examiners (PSI).

2Under the IPC, what is the DFU value for a standard water closet?

A.2 DFU

B.3 DFU

C.4 DFU

D.6 DFU

Explanation: Under the IPC, a standard water closet is 3 DFU. North Carolina plumbers use IPC DFU values.

3Under the IPC, minimum building sewer with water closets is?

A.2 inches

B.3 inches

C.4 inches

D.6 inches

Explanation: Minimum building sewer is 4 inches when water closets are connected. North Carolina follows IPC sewer sizing.

4Under the IPC, minimum vent pipe size is?

A.1 inch

B.1-1/4 inches

C.1-1/2 inches

D.2 inches

Explanation: No vent less than 1-1/4 inches under the IPC. North Carolina follows IPC vent sizing.

5Under the IPC, max static water pressure in a building is?

A.60 psi

B.80 psi

C.100 psi

D.120 psi

Explanation: Max static pressure is 80 psi. PRV required above 80. North Carolina follows IPC pressure limits.

6Under the IPC, high-hazard cross-connections require what backflow device?

A.AVB

B.Dual check

C.RPZ assembly

D.Hose bibb vacuum breaker

Explanation: RPZ required for high-hazard cross-connections. North Carolina plumbers select devices by hazard level.

7Under the IPC, minimum trap seal depth is?

A.1 inch

B.2 inches

C.3 inches

D.4 inches

Explanation: Minimum trap seal is 2 inches, maximum 4 inches. North Carolina plumbers maintain proper seals.

8Under the IPC, minimum lavatory trap size is?

A.1 inch

B.1-1/4 inches

C.1-1/2 inches

D.2 inches

Explanation: Minimum lavatory trap is 1-1/4 inches. North Carolina follows IPC trap sizing.

9Under the IPC, minimum building water service is?

A.1/2 inch

B.3/4 inch

C.1 inch

D.1-1/4 inches

Explanation: Minimum building water service is 3/4 inch. North Carolina plumbers size per IPC calculations.

10Under the IPC, what material is NOT approved for underground drainage?

A.Cast iron

B.PVC DWV

C.ABS DWV

D.Galvanized steel

Explanation: Galvanized steel corrodes underground. Cast iron, PVC, ABS are approved. North Carolina follows IPC material rules.

About the NC Plumbing Contractor Exam

North Carolina's plumbing exam is a contractor-level exam administered by PSI on behalf of the Board of Examiners. NC uses the NC State Plumbing Code, which is based on the IPC with state amendments. The exam covers drainage, venting, water supply, gas piping, and NC-specific requirements.

Questions

100 scored questions

Time Limit

3-4 hours

Passing Score

70%

Exam Fee

$25 + $100 license (NC Board of Examiners of Plumbing, Heating & Fire Sprinkler Contractors (PSI))

NC Plumbing Contractor Exam Content Outline

25%

Drainage, Waste & Vent Systems

NC SPC drainage pipe sizing, DFU calculations, slope requirements, cleanouts, and trap arm distances

20%

Venting Systems

Vent sizing, wet venting, AAVs, vent termination, and circuit venting per NC SPC

20%

Water Supply & Backflow Prevention

Water pipe sizing, WSFU calculations, backflow prevention, pressure regulation, and cross-connection control

15%

Gas Piping & Venting

Gas pipe sizing, BTUH calculations, pressure testing, combustion air, and appliance venting

20%

Code Administration & NC-Specific Rules

Permits, inspections, contractor responsibilities, NC state amendments, and business practices

How to Pass the NC Plumbing Contractor Exam

What You Need to Know

Passing score: 70%
Exam length: 100 questions
Time limit: 3-4 hours
Exam fee: $25 + $100 license

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

NC Plumbing Contractor Study Tips from Top Performers

1Study IPC-based content — NC's State Plumbing Code is based on the IPC with amendments

2Learn NC-specific amendments that differ from the standard IPC

3Master IPC drainage and vent sizing tables for pipe sizing questions

4Review contractor-level responsibilities including permits, inspections, and business practices

5Study backflow prevention device selection and cross-connection control

6Practice gas pipe sizing and BTUH calculations

Frequently Asked Questions

What plumbing code does North Carolina use?

North Carolina uses the NC State Plumbing Code (NC SPC), which is based on the International Plumbing Code (IPC) with state-specific amendments. IPC study materials are applicable with attention to NC amendments.

Is the NC exam a journeyman or contractor exam?

NC administers a contractor-level plumbing exam through the Board of Examiners of Plumbing, Heating & Fire Sprinkler Contractors. This is a higher-level exam that includes business and contracting knowledge in addition to technical plumbing code.

How much does the NC plumber exam cost?

The NC plumbing exam fee is $25 for the PSI exam, plus a $100 license fee to the Board of Examiners. Total initial cost is approximately $125.

What experience is needed for the NC plumbing contractor license?

NC requires documented plumbing experience under a licensed contractor. Contact the Board of Examiners for specific hour requirements and application procedures.