PLUMBER’S EXAM | INTERIOR DESIGN PROFESSIONAL EXAM
2026/2027 LATEST UPDATE | QUESTIONS AND VERIFIED ANSWERS
| GRADED A+
Of the four board subjects given for Master Plumbers examination, which of this subject was
originally split into two subjects?
A. Plumbing Code
B. Design and Installations
C. Plumbing Arithmetic
D. Practical Problems -
CORRECT|ANSWER
D
Copper tube and fittings used for drainage and vent piping installed aboveground shall be at least
____.
A. Type DWV
B. Type L
C. Type K
D. Type M -
CORRECT|ANSWER
A
A domestic dishwasher drain shall first connect to ____.
A. an approved airgap fitting
B. a double-check valve
C. a triple-check valve
D. an approved valve -
CORRECT|ANSWER
A
,Unions shall be installed in a water supply system within ____ to a water heater
A. 36 inches
B. 12 inches
C. 24 inches
D. 48 inches -
CORRECT|ANSWER
B
A branch line serving a trap in a combination waste and vent system is required to be separately
vented when the length of the branch exceeds ____.
A. 15
B. 10
C. 5
D. 25 -
CORRECT|ANSWER
A
Three-inch horizontal drainage piping shall be run in practical alignment and at a uniform slope of
not less than:
A. 1/4 inch per foot
B. 1/16 inch per foot
C. 1/2 inch per foot
D. 1/8 inch per foot -
CORRECT|ANSWER
A
The minimum requirement for the slope of horizontal drainage pipes between manholes is
, A. 4%
B. 2-1/2 %
C. 2%
D. 3% -
CORRECT|ANSWER
C
A drain connecting the compartments of a set of fixtures to its trap is called a(an) ____.
A. continuous waste
B. special waste
C. indirect waste
D. combination waste and vent -
CORRECT|ANSWER
A
The maximum number of lavatories on a 2-1/2 inch horizontal waste line is ____.
A. 10
B. 14
C. 20
D. 6 -
CORRECT|ANSWER
B
The maximum distance a gas shutoff valve may be from a gas appliance (except for range and dryer
connectors) is ____.
A. 6 feet
B. 10feet
C. 3 feet
2026/2027 LATEST UPDATE | QUESTIONS AND VERIFIED ANSWERS
| GRADED A+
Of the four board subjects given for Master Plumbers examination, which of this subject was
originally split into two subjects?
A. Plumbing Code
B. Design and Installations
C. Plumbing Arithmetic
D. Practical Problems -
CORRECT|ANSWER
D
Copper tube and fittings used for drainage and vent piping installed aboveground shall be at least
____.
A. Type DWV
B. Type L
C. Type K
D. Type M -
CORRECT|ANSWER
A
A domestic dishwasher drain shall first connect to ____.
A. an approved airgap fitting
B. a double-check valve
C. a triple-check valve
D. an approved valve -
CORRECT|ANSWER
A
,Unions shall be installed in a water supply system within ____ to a water heater
A. 36 inches
B. 12 inches
C. 24 inches
D. 48 inches -
CORRECT|ANSWER
B
A branch line serving a trap in a combination waste and vent system is required to be separately
vented when the length of the branch exceeds ____.
A. 15
B. 10
C. 5
D. 25 -
CORRECT|ANSWER
A
Three-inch horizontal drainage piping shall be run in practical alignment and at a uniform slope of
not less than:
A. 1/4 inch per foot
B. 1/16 inch per foot
C. 1/2 inch per foot
D. 1/8 inch per foot -
CORRECT|ANSWER
A
The minimum requirement for the slope of horizontal drainage pipes between manholes is
, A. 4%
B. 2-1/2 %
C. 2%
D. 3% -
CORRECT|ANSWER
C
A drain connecting the compartments of a set of fixtures to its trap is called a(an) ____.
A. continuous waste
B. special waste
C. indirect waste
D. combination waste and vent -
CORRECT|ANSWER
A
The maximum number of lavatories on a 2-1/2 inch horizontal waste line is ____.
A. 10
B. 14
C. 20
D. 6 -
CORRECT|ANSWER
B
The maximum distance a gas shutoff valve may be from a gas appliance (except for range and dryer
connectors) is ____.
A. 6 feet
B. 10feet
C. 3 feet
