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Per the Kentucky SPC, what is the minimum slope for a 4-inch horizontal drainage 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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Free Journeyman Plumber Practice Test by State 2026: 4,700+ Questions24 min read

2026 Statistics

Key Facts: KY Plumber Exam

70%

Passing Score

Kentucky Plumbing Division

~80

Exam Questions

PSI exam format

3 hrs

Time Limit

PSI

SPC/IPC

Code Base

Kentucky adoption

The Kentucky journeyman plumber exam is administered through PSI and overseen by the KY Department of Housing / Plumbing Division. The exam has approximately 80 multiple-choice questions with a 3-hour time limit, requiring 70% to pass. Kentucky uses the State Plumbing Code (SPC) based on the IPC. The exam is open-book, so candidates should bring a clean bound copy of the Kentucky SPC.

Sample KY Plumber Practice Questions

Try these sample questions to test your KY 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 Kentucky SPC, what is the minimum slope for a 4-inch horizontal drainage 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 Kentucky State Plumbing Code (based on IPC), a 4-inch or larger horizontal drainage pipe requires a minimum slope of 1/8 inch per foot. Pipes 3 inches or smaller require 1/4 inch per foot.

2A water closet (floor-mounted) has a DFU value of what according to the Kentucky SPC?

A.2 DFU

B.3 DFU

C.4 DFU

D.6 DFU

Explanation: Per the Kentucky SPC (based on IPC Table 709.1), a floor-mounted water closet with a 1.6 GPF flush valve has a DFU value of 4. This value is used for sizing the drainage system.

3What is the minimum size building drain required for a system with 180 DFUs?

A.3 inches

B.4 inches

C.5 inches

D.6 inches

Explanation: Per the Kentucky SPC drainage sizing tables, a 4-inch building drain at 1/8 inch per foot slope can handle up to 216 DFUs. Since 180 DFUs is within this capacity, a 4-inch pipe is the minimum required size.

4Where are cleanouts required in a building drainage system per Kentucky SPC?

A.At every change of direction greater than 45 degrees

B.At every change of direction greater than 90 degrees

C.Only at the building drain connection

D.Only at the base of each stack

Explanation: The Kentucky SPC requires cleanouts at each aggregate change of direction exceeding 135 degrees (equivalent to greater than 45 degrees from the flow direction), at intervals not exceeding 100 feet in horizontal drains, and at the upper terminal of each building drain.

5What is the maximum distance between cleanouts in a horizontal drainage line per Kentucky SPC?

A.50 feet

B.75 feet

C.100 feet

D.150 feet

Explanation: Per the Kentucky SPC, cleanouts must be installed at intervals not exceeding 100 feet in horizontal drainage lines. This ensures the entire drainage system can be accessed for maintenance and clearing blockages.

6A kitchen sink in a commercial restaurant has what DFU value per the Kentucky SPC?

A.1.5 DFU

B.2 DFU

C.3 DFU

D.4 DFU

Explanation: Per the Kentucky SPC, a kitchen sink (including commercial) is rated at 2 DFU. The fixture unit value is based on the probable discharge rate of the fixture, not the occupancy type.

7What is the minimum size of an individual fixture drain for a floor drain?

A.1-1/2 inches

B.2 inches

C.3 inches

D.4 inches

Explanation: Per the Kentucky SPC, the minimum drain size for a floor drain is 2 inches. Floor drains must connect to the drainage system with a trap and be sized to handle the anticipated flow.

8Horizontal drainage piping must be supported at intervals not exceeding what distance per Kentucky SPC?

A.4 feet

B.6 feet

C.8 feet

D.10 feet

Explanation: Per the Kentucky SPC, horizontal drainage piping must be supported at intervals based on pipe material, but the general requirement for most materials is support at intervals not exceeding 10 feet for 4-inch and larger pipe, and closer intervals for smaller pipe sizes.

9What is the minimum pipe size for a building sewer per the Kentucky SPC?

A.3 inches

B.4 inches

C.5 inches

D.6 inches

Explanation: Per the Kentucky SPC, the minimum building sewer size is 6 inches when connecting to the public sewer. This ensures adequate capacity for the building's total drainage discharge and accounts for future connections.

10What type of fitting is required for a change of direction from horizontal to vertical in the drainage system?

A.Short-sweep 1/4 bend

B.Long-sweep 1/4 bend

C.Sanitary tee

D.Either a short or long sweep fitting

Explanation: Per the Kentucky SPC, a change of direction from horizontal to vertical in the drainage system may use either a short-sweep or long-sweep quarter bend. The restriction on short-sweep fittings applies to horizontal-to-horizontal direction changes.

About the KY Plumber Exam

Kentucky journeyman plumber licensing exam administered by PSI and overseen by the Department of Housing, Buildings and Construction / Plumbing Division. Based on the Kentucky State Plumbing Code (SPC, derived from the International Plumbing Code). Covers drainage systems, water supply, venting, fixtures and appliances, gas piping, materials, and code administration. Approximately 80 multiple-choice questions with a 3-hour time limit.

Questions

80 scored questions

Time Limit

3 hours

Passing Score

70%

Exam Fee

$60 (Kentucky Department of Housing, Buildings and Construction / Plumbing Division)

KY Plumber Exam Content Outline

25%

Drainage Systems

Drain pipe sizing, fixture units (DFU), slope requirements, cleanouts, building sewers, indirect waste, and special drainage systems per Kentucky SPC

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%

Code Administration & Materials

Permits, inspections, plan review, approved materials, pipe materials, joint methods, hangers and supports, and Kentucky-specific amendments

How to Pass the KY Plumber Exam

What You Need to Know

Passing score: 70%
Exam length: 80 questions
Time limit: 3 hours
Exam fee: $60

Keys to Passing

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

KY Plumber Study Tips from Top Performers

1Study the Kentucky State Plumbing Code (SPC) thoroughly — learn to navigate the index and tables quickly for the open-book exam

2Master DFU calculations and drain pipe sizing using the SPC fixture unit tables

3Practice vent sizing and understand when wet venting, circuit venting, and air admittance valves are permitted

4Memorize minimum pipe sizes for common fixtures and trap arm distances

5Review backflow prevention device selection based on hazard level (high vs. low hazard)

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 Kentucky-specific amendments to the IPC that may appear on the exam

Frequently Asked Questions

How hard is the Kentucky journeyman plumber exam?

The Kentucky journeyman plumber exam is moderately challenging with an estimated 55-65% pass rate. The exam has approximately 80 questions based on the Kentucky State Plumbing Code (derived from IPC) and requires 70% to pass. Strong knowledge of pipe sizing, DFU calculations, and venting requirements is essential.

What plumbing code does Kentucky use?

Kentucky uses the State Plumbing Code (SPC), which is based on the International Plumbing Code (IPC) with Kentucky-specific amendments. A clean, bound copy of the Kentucky SPC is typically allowed as a reference during the PSI-administered exam.

How much does the Kentucky plumber exam cost?

The Kentucky journeyman plumber exam fee is approximately $60 for the PSI exam. Additional costs may include the application fee and Kentucky SPC code book. Check with the KY Department of Housing / Plumbing Division for the most current fee schedule.

What are the experience requirements for Kentucky journeyman plumber?

Kentucky typically requires completion of a plumbing apprenticeship or equivalent experience under a licensed plumber. Contact the Kentucky Department of Housing, Buildings and Construction / Plumbing Division for detailed eligibility requirements and approved experience documentation.