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100+ Free MS Plumbing Practice Questions

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2026 Statistics

Key Facts: MS Plumbing Exam

70%

Passing Score

PSI MS Contractor Bulletin 4/23/2026

70 Q

Official Exam Questions

PSI MS Contractor Bulletin 4/23/2026

3 hours

Time Allowed

PSI MS Contractor Bulletin 4/23/2026

$120

PSI Exam Fee

PSI MS Contractor Bulletin 4/23/2026

Open book

Exam Format

PSI MS Contractor Bulletin 4/23/2026

MS Plumbing PSI trade exam: 70 questions, 70% pass, 3 hours, fee $120. Open-book MSBOC classification (bulletin 4/23/2026).

Sample MS Plumbing Practice Questions

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

1Per IPC 2021 Section 301.7, if a manufacturer's installation instructions conflict with a requirement of the code, which provision applies?
A.The manufacturer's instructions always control
B.The less restrictive provision applies
C.The more restrictive provision applies
D.The contractor may choose either provision
Explanation: IPC 301.7 states that where conflicts occur between this code and the manufacturer's installation instructions, the more restrictive provisions shall apply. That rule keeps the installation at least as safe and durable as the code minimum. The Mississippi Plumbing Contractor exam is open-book, so locate this general-regulation rule in Chapter 3 rather than guessing from field habit.
2Per IPC 2021 Section 301.6, plumbing systems are prohibited in an elevator shaft or elevator equipment room except that floor drains, sumps, and sump pumps at the base of the shaft are permitted when they are which of the following?
A.Directly connected to the sanitary stack with a sanitary tee
B.Indirectly connected to the plumbing system and comply with the oil-separator rules of Section 1003.4
C.Connected to a grease interceptor serving the building kitchen
D.Omitted if the elevator pit is waterproofed
Explanation: IPC 301.6 prohibits plumbing in elevator shafts and elevator equipment rooms. The exception allows floor drains, sumps, and sump pumps at the base of the shaft only when they are indirectly connected and comply with Section 1003.4 oil-separator requirements. Direct sanitary connections and kitchen grease interceptors do not satisfy that elevator-pit exception.
3Per IPC 2021 Section 303.3, plastic pipe, fittings, and components used in a plumbing system shall be third-party certified as conforming to which standard?
A.NSF 14
B.NSF 61 only, with no plastic-pipe listing
C.ASTM A74
D.CISPI 301
Explanation: IPC 303.3 requires plastic pipe, fittings, and components to be third-party certified as conforming to NSF 14. NSF 61 addresses drinking-water health effects of water-supply products, not the plastic-pipe product listing required by 303.3. ASTM A74 and CISPI 301 are cast-iron soil-pipe standards.
4A drainage and vent system is water-tested in sections per IPC 2021 Section 312.2. What is the minimum test head and minimum hold time for each section?
A.5-foot head of water held for 10 minutes
B.10-foot head of water held for not less than 15 minutes
C.15-foot head of water held for 5 minutes
D.A 5 psi air test held for 30 minutes
Explanation: IPC 312.2 requires each tested section to be filled with water, but sections shall not be tested with less than a 10-foot head of water, and that pressure shall be held for not less than 15 minutes. The system must then be tight at all points. A 5 psi air test is a separate method under 312.3 and is not permitted on plastic piping.
5Per IPC 2021 Section 312.3, which statement about drainage and vent air testing is correct?
A.Plastic piping shall not be tested using air
B.Plastic piping may be air-tested at 5 psi for 15 minutes
C.An air test of 50 psi is required on all DWV systems
D.Air testing is never permitted on any drainage piping
Explanation: IPC 312.3 opens with a hard prohibition: plastic piping shall not be tested using air. Where air testing is used on non-plastic drainage and vent piping, the system is pressurized to a uniform 5 psi (or a 10-inch mercury column) and held for not less than 15 minutes. The 50 psi air option in 312.5 applies to water-supply piping that is not plastic, not to DWV.
6A plumber is selecting a test gauge for a 5 psi drainage air test. Per IPC 2021 Section 312.1.1, what is the maximum permitted gauge increment?
A.0.10 psi
B.1 psi
C.2 psi
D.5 psi
Explanation: IPC 312.1.1 ties gauge resolution to the test pressure. Tests requiring 10 psi or less shall use a gauge with increments of 0.10 psi or less. A 5 psi DWV air test therefore needs a tenth-pound gauge so a small leak is visible. One-psi increments are only allowed between greater than 10 psi and 100 psi, and 2 psi increments are for tests greater than 100 psi.
7On a construction walking/working surface with an unprotected side or edge, OSHA 29 CFR 1926.501 generally requires fall protection when the employee is how far above a lower level?
A.4 feet
B.6 feet
C.10 feet
D.15 feet
Explanation: OSHA 1926.501(b)(1) requires each employee on a walking/working surface with an unprotected side or edge 6 feet or more above a lower level to be protected by a guardrail system, safety net system, or personal fall arrest system. The 4-foot trigger is the general-industry rule in 1910, not construction. Plumbing contractors working on roofs, mezzanines, and open floors must plan fall protection at 6 feet.
8When a portable ladder is used to reach an upper landing, OSHA 29 CFR 1926.1053 requires the side rails to extend how far above that landing unless the ladder is secured and a grasping device is provided?
A.1 foot
B.2 feet
C.3 feet
D.6 feet
Explanation: OSHA 1926.1053(b)(1) requires portable-ladder side rails to extend at least 3 feet above the upper landing surface. If that extension is impossible because of ladder length, the ladder must be secured at the top and a grasping device such as a grab rail must be provided. The 3-foot extension is one of the most-cited ladder rules on construction sites.
9Unless the excavation is entirely in stable rock or a registered professional engineer designs a different system, OSHA 29 CFR 1926.652 requires a protective system for employees in a trench that is how deep or deeper?
A.4 feet
B.5 feet
C.6 feet
D.8 feet
Explanation: OSHA 1926.652(a)(1) requires a protective system in excavations 5 feet or deeper unless the excavation is made entirely in stable rock or a registered professional engineer determines that no cave-in potential exists. Four feet is the depth that triggers a stairway, ladder, or ramp for egress, not the cave-in protection trigger. Plumbing sewer and water-service trenches commonly exceed 5 feet and need sloping, shoring, or shielding.
10A plumber is working in a trench that is 6 feet deep and 70 feet long. Per OSHA 29 CFR 1926.651(c)(2), what is the maximum lateral travel distance to a ladder, stairway, or ramp used as a means of egress?
A.15 feet
B.25 feet
C.50 feet
D.75 feet
Explanation: OSHA 1926.651(c)(2) requires a stairway, ladder, ramp, or other safe means of egress in trench excavations 4 feet or more in depth so that no employee must travel more than 25 feet laterally to the egress. A 70-foot trench therefore needs egress at intervals that keep every worker within 25 feet. The 5-foot protective-system rule is a separate requirement and does not change the 25-foot travel limit.

About the MS Plumbing Exam

Mississippi Plumbing Contractor Examination is a classification trade examination administered by PSI for the Mississippi State Board of Contractors. The official open-book exam has 70 questions, a 70% passing standard, and 3 hours allowed. PSI examination fee is $120 per portion (bulletin updated 4/23/2026). This English-language MCQ bank is a study aid for the official content outline; it is not an official PSI form, does not replace the required Law and Business Management exam, and is not a substitute for MSBOC application review or the official open-book examination.

Questions

70 scored questions

Time Limit

3 hours

Passing Score

70%

Exam Fee

$120 (PSI Services LLC (for Mississippi State Board of Contractors))

MS Plumbing Exam Content Outline

6%

General Plumbing Regulations

IPC administration and general regulations

6%

Safety

Plumbing safety

6%

Cleanouts

Cleanouts

7%

Fixtures and Equipment

Fixtures and equipment

3%

Water Heaters

Water heaters

4%

Piping, valves, controls

Piping, valves, and controls

9%

Water Supply

Water supply and distribution

4%

Hangers and Supports

Hangers and supports

21%

Drain, Waste, and Vent

DWV systems

4%

Backflow

Backflow prevention

6%

Traps and Interceptors

Traps and interceptors

3%

Developed length

Developed length

17%

Isometric Analysis

Isometric plan reading

4%

Joints and Connections

Joints and connections

How to Pass the MS Plumbing Exam

What You Need to Know

  • Passing score: 70%
  • Exam length: 70 questions
  • Time limit: 3 hours
  • Exam fee: $120

Keys to Passing

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

MS Plumbing Study Tips from Top Performers

1Study only the approved references listed for this classification in the current PSI Mississippi Contractor bulletin (updated 4/23/2026)
2Practice open-book navigation with permanent tabs and indexes before test day
3Drill OSHA 29 CFR 1926 topics that appear across nearly every trade outline
4Confirm MSBOC classification scope and eligibility at msboc.us before scheduling with PSI
5All applicants must also pass Law and Business Management unless it is waived

Frequently Asked Questions

How many questions are on the MS Plumbing exam?

The official PSI examination has 70 scored questions (plus possible unscored experimental items). Passing is 70% within 3 hours.

How much does the MS Plumbing exam cost?

PSI lists $120 per examination portion (Candidate Information Bulletin updated 4/23/2026). MSBOC application fees are separate: $400 commercial or $50 residential. Additional classifications are $100 each.

Is the Mississippi contractor exam open book?

Yes. PSI administers MSBOC classification exams as open book. Only bulletin-listed approved references are allowed; temporary tabs such as Post-it notes are prohibited.

Do I still need the Law and Business Management exam?

Yes. MSBOC requires the Mississippi Law and Business Management exam (50 questions, 70%, 2 hours) of all applicants. Reciprocity may waive a trade exam in some cases but does not waive Law and Business.