LATEST NCCER PLUMBING LEVEL 2
CERTIFICATION EXAM OFFERED BY
NCCER (NATIONAL CENTER FOR
CONSTRUCTION EDUCATION AND
RESEARCH) | Q&A WITH RATIONALES
1. What is the minimum required distance from a
water closet flange to a side wall or obstruction?
A) 12 inches
B) 15 inches
C) 18 inches
D) 21 inches
Correct answer: B
Rationale: Most plumbing codes require a minimum
clearance of 15 inches from the centerline of the
water closet to any side wall, vanity, or other
obstruction.
2. The rough-in dimension for a typical residential
water closet measured from the finished wall to the
center of the closet flange is:
A) 10 inches
,B) 12 inches
C) 14 inches
D) 16 inches
Correct answer: B
Rationale: Standard water closet rough-in distance is
12 inches, though 10-inch and 14-inch are available
for special situations.
3. Which type of bathtub drain typically includes an
integral overflow and is connected to a waste and
overflow assembly?
A) Pop-up drain
B) Trip-lever drain
C) Toe-tap drain
D) Grid drain
Correct answer: B
Rationale: A trip-lever drain has an overflow plate
with a lever that operates the drain stopper via
linkage; it is common in residential tubs.
4. What is the minimum trap size for a residential
bathtub?
A) 1-1/2 inches
,B) 2 inches
C) 2-1/2 inches
D) 3 inches
Correct answer: A
Rationale: Bathtub traps are typically 1-1/2 inches,
though some codes require 2 inches for shower
receptors.
5. A shower receptor must have a minimum finished
interior size of:
A) 900 square inches
B) 1024 square inches
C) 1200 square inches
D) 1500 square inches
Correct answer: B
Rationale: The minimum finished interior size for a
shower receptor is 1,024 square inches (e.g., 32" ×
32").
6. What is the minimum required trap size for a
residential shower?
A) 1-1/2 inches
B) 2 inches
, C) 2-1/2 inches
D) 3 inches
Correct answer: B
Rationale: Shower drains and traps are required to
be a minimum of 2 inches to handle the higher flow
rate.
7. A kitchen sink with a garbage disposer typically
requires a trap size of:
A) 1-1/4 inches
B) 1-1/2 inches
C) 2 inches
D) 2-1/2 inches
Correct answer: B
Rationale: Kitchen sink traps are typically 1-1/2
inches, though 2-inch is allowed for commercial
applications.
8. The maximum developed length of a 1-1/2 inch trap
arm from trap weir to vent connection is:
A) 3 feet
B) 4 feet
C) 5 feet
CERTIFICATION EXAM OFFERED BY
NCCER (NATIONAL CENTER FOR
CONSTRUCTION EDUCATION AND
RESEARCH) | Q&A WITH RATIONALES
1. What is the minimum required distance from a
water closet flange to a side wall or obstruction?
A) 12 inches
B) 15 inches
C) 18 inches
D) 21 inches
Correct answer: B
Rationale: Most plumbing codes require a minimum
clearance of 15 inches from the centerline of the
water closet to any side wall, vanity, or other
obstruction.
2. The rough-in dimension for a typical residential
water closet measured from the finished wall to the
center of the closet flange is:
A) 10 inches
,B) 12 inches
C) 14 inches
D) 16 inches
Correct answer: B
Rationale: Standard water closet rough-in distance is
12 inches, though 10-inch and 14-inch are available
for special situations.
3. Which type of bathtub drain typically includes an
integral overflow and is connected to a waste and
overflow assembly?
A) Pop-up drain
B) Trip-lever drain
C) Toe-tap drain
D) Grid drain
Correct answer: B
Rationale: A trip-lever drain has an overflow plate
with a lever that operates the drain stopper via
linkage; it is common in residential tubs.
4. What is the minimum trap size for a residential
bathtub?
A) 1-1/2 inches
,B) 2 inches
C) 2-1/2 inches
D) 3 inches
Correct answer: A
Rationale: Bathtub traps are typically 1-1/2 inches,
though some codes require 2 inches for shower
receptors.
5. A shower receptor must have a minimum finished
interior size of:
A) 900 square inches
B) 1024 square inches
C) 1200 square inches
D) 1500 square inches
Correct answer: B
Rationale: The minimum finished interior size for a
shower receptor is 1,024 square inches (e.g., 32" ×
32").
6. What is the minimum required trap size for a
residential shower?
A) 1-1/2 inches
B) 2 inches
, C) 2-1/2 inches
D) 3 inches
Correct answer: B
Rationale: Shower drains and traps are required to
be a minimum of 2 inches to handle the higher flow
rate.
7. A kitchen sink with a garbage disposer typically
requires a trap size of:
A) 1-1/4 inches
B) 1-1/2 inches
C) 2 inches
D) 2-1/2 inches
Correct answer: B
Rationale: Kitchen sink traps are typically 1-1/2
inches, though 2-inch is allowed for commercial
applications.
8. The maximum developed length of a 1-1/2 inch trap
arm from trap weir to vent connection is:
A) 3 feet
B) 4 feet
C) 5 feet
