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Per the IPC as adopted by Mississippi, what is the minimum slope for a 4-inch horizontal drain pipe?

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: MS Plumber Exam

70%

Passing Score

MS Board of Contractors

~80

Exam Questions

PSI exam format

Trade+Biz

Exam Components

Two-part exam

IPC

Code Base

Mississippi adoption

The Mississippi journeyman plumber exam is administered through PSI and overseen by the State Board of Contractors. The exam includes both trade knowledge and business exam components, which is unique among plumber exams. Mississippi uses the International Plumbing Code (IPC). Exam fees range from $50 to $400 depending on the license classification. Requires 70% to pass.

Sample MS Plumber Practice Questions

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

1Per the IPC as adopted by Mississippi, what is the minimum slope for a 4-inch horizontal drain pipe?

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: Per the International Plumbing Code (IPC), horizontal drainage pipes 4 inches and larger require a minimum slope of 1/8 inch per foot. Pipes 3 inches or smaller require 1/4 inch per foot minimum slope.

2Per the IPC, what is the DFU value for a floor-mounted water closet (1.6 GPF)?

A.2 DFU

B.3 DFU

C.4 DFU

D.6 DFU

Explanation: Per the International Plumbing Code (IPC) fixture unit table, a floor-mounted water closet with a 1.6 GPF rating has a DFU value of 4. This is the standard value used for drainage system sizing.

3What is the minimum building drain size for a system with 200 DFUs per the IPC as adopted by Mississippi?

A.3 inches

B.4 inches

C.5 inches

D.6 inches

Explanation: Per the International Plumbing Code (IPC) drainage sizing tables, a 4-inch building drain at 1/8 inch per foot slope can handle up to approximately 216 DFUs, so 4 inches is adequate for 200 DFUs.

4Per the IPC, cleanouts in horizontal drains must be installed at intervals not exceeding what distance?

A.50 feet

B.75 feet

C.100 feet

D.125 feet

Explanation: Per the International Plumbing Code (IPC), cleanouts must be installed at maximum 100-foot intervals in horizontal drainage lines. They are also required at changes of direction and at the upper terminal of the building drain.

5Per the IPC, what is the minimum slope for a 2-inch horizontal drain pipe?

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: Per the International Plumbing Code (IPC), horizontal drainage pipes 3 inches and smaller (including 2-inch) require a minimum slope of 1/4 inch per foot to maintain adequate flow velocity.

6Per the IPC as adopted by Mississippi, a lavatory has what DFU value?

A.0.5 DFU

B.1 DFU

C.1.5 DFU

D.2 DFU

Explanation: Per the International Plumbing Code (IPC) fixture unit table, a lavatory has a DFU value of 1. This is one of the lowest individual fixture DFU ratings.

7What is the minimum trap size for a kitchen sink per the IPC?

A.1-1/4 inches

B.1-1/2 inches

C.2 inches

D.3 inches

Explanation: Per the International Plumbing Code (IPC), the minimum trap and drain size for a kitchen sink is 1-1/2 inches.

8Per the IPC, what fitting is required for a horizontal-to-horizontal direction change in drainage piping?

A.Short-sweep quarter bend

B.Long-sweep quarter bend or equivalent

C.Standard tee fitting

D.Any available fitting

Explanation: Per the International Plumbing Code (IPC), horizontal-to-horizontal changes of direction must use long-sweep fittings. Short-sweep fittings are restricted to horizontal-to-vertical transitions.

9Per the IPC, indirect waste from a commercial dishwasher must discharge through what?

A.A direct connection to the building drain

B.An air gap to an approved receptor

C.A check valve

D.A backwater valve

Explanation: Per the International Plumbing Code (IPC), indirect waste from commercial food equipment must discharge through an air gap into an approved floor sink or receptor to prevent contamination.

10Per the IPC, what is the maximum DFU load on a 3-inch horizontal branch at 1/4 inch per foot slope?

A.20 DFU

B.27 DFU

C.36 DFU

D.42 DFU

Explanation: Per the International Plumbing Code (IPC) drainage table, a 3-inch horizontal branch at 1/4 inch per foot slope handles a maximum of 36 DFUs.

About the MS Plumber Exam

Mississippi journeyman plumber licensing exam administered by PSI and overseen by the State Board of Contractors. Includes both trade and business exam components based on the International Plumbing Code (IPC). Covers drainage systems, water supply, venting, fixtures, gas piping, materials, and business/code administration. Requires 70% to pass.

Questions

80 scored questions

Time Limit

3 hours

Passing Score

70%

Exam Fee

$50-$400 (Mississippi State Board of Contractors)

MS Plumber Exam Content Outline

25%

Drainage Systems

Drain pipe sizing, DFU calculations, slope requirements, cleanouts, building sewers, indirect waste, and special drainage systems per IPC

20%

Water Supply Systems

Water pipe sizing, WSFU calculations, backflow prevention, pressure regulation, water heaters, cross-connection control, and potable water protection

20%

Venting Systems

Vent sizing, wet venting, circuit venting, air admittance valves, vent termination, combination waste and vent, and trap seal protection

15%

Fixtures & Appliances

Fixture installation requirements, clearances, accessible fixtures, commercial fixtures, water closets, lavatories, showers, and bathtubs

10%

Gas Piping

Gas pipe sizing, BTU calculations, appliance venting, pressure testing, combustion air, and fuel gas code compliance

10%

Business & Code Administration

Business practices, permits, inspections, plan review, approved materials, contractor regulations, and Mississippi-specific requirements

How to Pass the MS Plumber Exam

What You Need to Know

Passing score: 70%
Exam length: 80 questions
Time limit: 3 hours
Exam fee: $50-$400

Keys to Passing

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

MS Plumber Study Tips from Top Performers

1Study the IPC thoroughly — learn to navigate the index and tables quickly for the open-book PSI exam

2Prepare for the business exam component — review contractor regulations, estimating, and business practices

3Master DFU calculations and drain pipe sizing using IPC fixture unit tables

4Practice vent sizing and understand when wet venting, circuit venting, and air admittance valves are permitted

5Review backflow prevention device selection based on hazard level per IPC

6Study water heater installation requirements including T&P relief valve discharge

7Practice gas pipe sizing calculations using BTU input ratings and pipe length tables

8Review Mississippi-specific contractor regulations and State Board of Contractors requirements

Frequently Asked Questions

How hard is the Mississippi journeyman plumber exam?

The Mississippi journeyman plumber exam is moderately challenging with an estimated 55-65% pass rate. The exam is based on the IPC and requires 70% to pass. Mississippi is unique in requiring both trade and business exam components, so candidates must prepare for business-related questions in addition to technical plumbing knowledge.

What is the business exam component?

Mississippi requires a business exam in addition to the trade knowledge exam. The business portion covers contractor regulations, business practices, estimating, project management, and Mississippi-specific contractor licensing requirements. Both components must be passed to obtain the license.

What plumbing code does Mississippi use?

Mississippi uses the International Plumbing Code (IPC) for its journeyman plumber exam. A clean, bound copy of the IPC is typically allowed as a reference during the PSI-administered exam. Check with the State Board of Contractors for the current adopted edition.

Why do Mississippi plumber exam fees vary so much?

Mississippi exam fees range from $50 to $400 depending on the license classification and scope of work. Higher classifications that allow larger project values have higher fees. Check with the State Board of Contractors for the specific fee for your desired license classification.