IRC Plumbing Practice Test Question
With Correct Solutions
What is the minimum size of a water meter and service piping in inches for a water
supply system of 34 fixture units with a maximum developed length of 200 feet. The
water pressure of the system is 35 psi. - Answer -✔✔1
Table AP201.1
What is the minimum sized trap that can be used for the drainage system of a bathtub
(with or without shower head and/or whirlpool attachments)? - Answer -✔✔1.5
Table P3201.7
A water heater pan drain must extend full-size and terminate over a suitably located
indirect waste receptor or must extend to the exterior of the building and terminate not
less than _____ inches and not more than _____ inches above the adjacent ground
surface. - Answer -✔✔6, 24
P2801.6.2
A laundry tray waste line is permitted to connect into a standpipe for automatic clothes
washer drain. The standpipe must extend not less than _____ above the trap weir and
must extend above the flood level rim of the laundry tray. - Answer -✔✔30 inches (762
mm)
P2706.1.2.1
Clothes closets, linen closets and pantries not exceeding _____ in area, with the
smallest dimension not greater than 3 feet (915 mm) and having wall and ceiling
surfaces of gypsum board will not require fire sprinklers. - Answer -✔✔24 square feet
(2.2 m2)
P2904.1.1
If a water closet can be removed to provide cleanout access, does that fulfill the
cleanout requirement of the code? - Answer -✔✔No
P3005.2.3
Appliances and equipment used for heating water or storing hot water have to be
protected by _____. - Answer -✔✔pressure-relief valve and temperature-relief valve or
a combination pressure and temperature-relief valve.
,P2804.1
Where the fixture drains connect at different levels, the common vent must connect as a
_____ extension of the _____ drain. - Answer -✔✔vertical, vertical
P3107.3
The minimum air gap distance in inches for lavatories and other fixtures with effective
opening not greater than 1/2 inch in diameter that are close to a wall is: - Answer -
✔✔1.5
Table P2902.3.1
In areas prone to flooding as established by the code, water supply systems must be
designed and constructed to prevent _____ of floodwaters. - Answer -✔✔infiltration
P2602.2
When either a public water-supply or sewer system, or both, are not available, _____,
an individual water-supply or individual sewage-disposal system, or both, must be
provided. - Answer -✔✔or connection thereto is not feasible
P2602.1
_____ installed in a bathroom are not required to be installed within an enclosure. -
Answer -✔✔direct-vent water heaters
M2005.2
For water supply systems used predominantly for flush tanks having a water supply
fixture unit load of 12, what is the comparable demand in gallons per minute. - Answer -
✔✔16.0
Table P2903.6(1)
Test equipment, materials and labor must be furnished by the ______ - Answer -
✔✔permittee
P2503.3
The minimum size in inches of a combination waste and vent pipe connecting to a
building drain or building sub drain and serving 31 d.f.u. is _____. - Answer -✔✔3
Table 3111.3
,The outlet of a water heaters pressure relief valve, temperature relief valve or
combination valve, must be directly connected to the _____. - Answer -✔✔none of the
above
P2804.6.1
What is the minimum pipe support spacing in feet, required for copper or copper alloy
tubing (1 1/4 inch diameter and smaller_ installed in a horizontal orientation. - Answer -
✔✔6
Table P2605.1
The flow velocity of the water distribution system must be controlled to reduce the
possibility of _____. - Answer -✔✔water hammer
P2903.5
A wet 2 inch vent can handle venting for _____ fixture unit loads. - Answer -✔✔4
Table P3108.3
There must be at least _____ inches clearance in front of the water closet, bidet or
lavatory to any wall, fixture or door. - Answer -✔✔21
P2705.1
Open hub waste receptors must be permitted in the form of a hub or pipe extending not
less than _____ inch(es) above a water impervious floor, and are not required to have a
strainer. - Answer -✔✔1
P2706.1
The minimum air gap distance in inches for sink, laundry trays, gooseneck back faucets
and other fixtures with effective openings not greater than 3/4 inch in diameter that are
away from a wall is: - Answer -✔✔1.5
Table P2902.3.1
Where the drainage piping has been roughed-in for future fixtures, a rough-in
connection for a vent must be installed a minimum of _____. - Answer -✔✔one-half
times the diameter of the drain
P3104.6
, Grinder pumps or grinder ejectors that receive the discharge of water closets must have
a minimum discharge opening of _____. - Answer -✔✔1 1/4 inches (32 mm)
P3007.6
The minimum air gap distance in inches for over-rim bath fillers and other fixtures with
effective openings not greater than 1 inch in diameter that are away from a wall is: -
Answer -✔✔2
Table P2902.3.1
What is the minimum size of a water meter and service piping in inches for a water
supply system of 21 fixture units with a maximum developed length of 500 feet. The
water pressure of the system is 48 psi. - Answer -✔✔1.5
Table AP 201.1
A _____ strainer or basket must cover the waste outlet of waste receptors. - Answer -
✔✔removable
P2706.1
Joints in plastic piping must be made with approved fittings by ______. - Answer -✔✔1.
solvent cementing; or
2. heat fusion; or
3. corrosion-resistant metal clamps with insert fittings or compression connections
P2906.9
For a fire sprinkler system the service line is a 3/4" pipe 78 feet in length. The required
flow rate at the sprinklers is 12 gpm. Determine the pressure loss in pound per square
inch (psi), in the water service pipe based on the selected size of the water service. -
Answer -✔✔24.9
Table P2904.6.2(1)
Joints and connections in the plumbing system must be ______ for the intended use or
required test pressure. - Answer -✔✔gas tight and water tight
P2906.8
What is the minimum size of distribution piping in inches for a water supply system of 80
fixture units with a maximum developed length of 150 feet. The water pressure of the
system is 70 psi. - Answer -✔✔1.25
With Correct Solutions
What is the minimum size of a water meter and service piping in inches for a water
supply system of 34 fixture units with a maximum developed length of 200 feet. The
water pressure of the system is 35 psi. - Answer -✔✔1
Table AP201.1
What is the minimum sized trap that can be used for the drainage system of a bathtub
(with or without shower head and/or whirlpool attachments)? - Answer -✔✔1.5
Table P3201.7
A water heater pan drain must extend full-size and terminate over a suitably located
indirect waste receptor or must extend to the exterior of the building and terminate not
less than _____ inches and not more than _____ inches above the adjacent ground
surface. - Answer -✔✔6, 24
P2801.6.2
A laundry tray waste line is permitted to connect into a standpipe for automatic clothes
washer drain. The standpipe must extend not less than _____ above the trap weir and
must extend above the flood level rim of the laundry tray. - Answer -✔✔30 inches (762
mm)
P2706.1.2.1
Clothes closets, linen closets and pantries not exceeding _____ in area, with the
smallest dimension not greater than 3 feet (915 mm) and having wall and ceiling
surfaces of gypsum board will not require fire sprinklers. - Answer -✔✔24 square feet
(2.2 m2)
P2904.1.1
If a water closet can be removed to provide cleanout access, does that fulfill the
cleanout requirement of the code? - Answer -✔✔No
P3005.2.3
Appliances and equipment used for heating water or storing hot water have to be
protected by _____. - Answer -✔✔pressure-relief valve and temperature-relief valve or
a combination pressure and temperature-relief valve.
,P2804.1
Where the fixture drains connect at different levels, the common vent must connect as a
_____ extension of the _____ drain. - Answer -✔✔vertical, vertical
P3107.3
The minimum air gap distance in inches for lavatories and other fixtures with effective
opening not greater than 1/2 inch in diameter that are close to a wall is: - Answer -
✔✔1.5
Table P2902.3.1
In areas prone to flooding as established by the code, water supply systems must be
designed and constructed to prevent _____ of floodwaters. - Answer -✔✔infiltration
P2602.2
When either a public water-supply or sewer system, or both, are not available, _____,
an individual water-supply or individual sewage-disposal system, or both, must be
provided. - Answer -✔✔or connection thereto is not feasible
P2602.1
_____ installed in a bathroom are not required to be installed within an enclosure. -
Answer -✔✔direct-vent water heaters
M2005.2
For water supply systems used predominantly for flush tanks having a water supply
fixture unit load of 12, what is the comparable demand in gallons per minute. - Answer -
✔✔16.0
Table P2903.6(1)
Test equipment, materials and labor must be furnished by the ______ - Answer -
✔✔permittee
P2503.3
The minimum size in inches of a combination waste and vent pipe connecting to a
building drain or building sub drain and serving 31 d.f.u. is _____. - Answer -✔✔3
Table 3111.3
,The outlet of a water heaters pressure relief valve, temperature relief valve or
combination valve, must be directly connected to the _____. - Answer -✔✔none of the
above
P2804.6.1
What is the minimum pipe support spacing in feet, required for copper or copper alloy
tubing (1 1/4 inch diameter and smaller_ installed in a horizontal orientation. - Answer -
✔✔6
Table P2605.1
The flow velocity of the water distribution system must be controlled to reduce the
possibility of _____. - Answer -✔✔water hammer
P2903.5
A wet 2 inch vent can handle venting for _____ fixture unit loads. - Answer -✔✔4
Table P3108.3
There must be at least _____ inches clearance in front of the water closet, bidet or
lavatory to any wall, fixture or door. - Answer -✔✔21
P2705.1
Open hub waste receptors must be permitted in the form of a hub or pipe extending not
less than _____ inch(es) above a water impervious floor, and are not required to have a
strainer. - Answer -✔✔1
P2706.1
The minimum air gap distance in inches for sink, laundry trays, gooseneck back faucets
and other fixtures with effective openings not greater than 3/4 inch in diameter that are
away from a wall is: - Answer -✔✔1.5
Table P2902.3.1
Where the drainage piping has been roughed-in for future fixtures, a rough-in
connection for a vent must be installed a minimum of _____. - Answer -✔✔one-half
times the diameter of the drain
P3104.6
, Grinder pumps or grinder ejectors that receive the discharge of water closets must have
a minimum discharge opening of _____. - Answer -✔✔1 1/4 inches (32 mm)
P3007.6
The minimum air gap distance in inches for over-rim bath fillers and other fixtures with
effective openings not greater than 1 inch in diameter that are away from a wall is: -
Answer -✔✔2
Table P2902.3.1
What is the minimum size of a water meter and service piping in inches for a water
supply system of 21 fixture units with a maximum developed length of 500 feet. The
water pressure of the system is 48 psi. - Answer -✔✔1.5
Table AP 201.1
A _____ strainer or basket must cover the waste outlet of waste receptors. - Answer -
✔✔removable
P2706.1
Joints in plastic piping must be made with approved fittings by ______. - Answer -✔✔1.
solvent cementing; or
2. heat fusion; or
3. corrosion-resistant metal clamps with insert fittings or compression connections
P2906.9
For a fire sprinkler system the service line is a 3/4" pipe 78 feet in length. The required
flow rate at the sprinklers is 12 gpm. Determine the pressure loss in pound per square
inch (psi), in the water service pipe based on the selected size of the water service. -
Answer -✔✔24.9
Table P2904.6.2(1)
Joints and connections in the plumbing system must be ______ for the intended use or
required test pressure. - Answer -✔✔gas tight and water tight
P2906.8
What is the minimum size of distribution piping in inches for a water supply system of 80
fixture units with a maximum developed length of 150 feet. The water pressure of the
system is 70 psi. - Answer -✔✔1.25
