PLUMBING C-36: WATER SUPPLY
SYSTEMS EXAM WITH CORRECT
QUESTIONS AND ANSWERS 2025
(1.) Of the following valves, the one code-approved for a building water service line is the: -
CORRECT-ANSWERSgate valve.
(2.) A water heater must have shut-off valve in the cold water supply line. The valve location
should not exceed _____ feet from the water heater. - CORRECT-ANSWERS3
(3.) A device used to prevent backflow by siphonic action is called a: - CORRECT-
ANSWERSvacuum breaker.
(4.) In a location where higher water pressure is unavailable, how can water line friction loss be
overcome? - CORRECT-ANSWERSBy increasing pipe diameter
(5.) What governs the actual cutting of an opening? - CORRECT-ANSWERSThe type of
material
(6.) The plumber uses a variety of tools to do his job; what are the advantages of using a strap
wrench when installing the lavatory? - CORRECT-ANSWERSIt will not damage the chrome
finish of the pipe
,(7.) What is the purpose of pipe "snaking" in trenches? - CORRECT-ANSWERSThermal
expansion
(8.) The top edge over which water in a receptor can overflow is called the: - CORRECT-
ANSWERSflood level rim.
(9.) Some solder used for copper pipe and fitting is composed of: - CORRECT-ANSWERS95%
tin, 5% antimony.
(10.) When may previously used piping material be reused in a potable water supply system? -
CORRECT-ANSWERSWhen its previous use was for a potable water supply system
(11.) To prevent summer condensation on the outside of a cold water pipe, you should: -
CORRECT-ANSWERSinsulate the pipe.
(12.) What is probably the most reliable method for finding the exact location and depth of a
buried pipe? - CORRECT-ANSWERSProbing
(13.) How should holes be made in a line of wall studs to install a water supply pipe? -
CORRECT-ANSWERSDrill in the center
(14.) What type of piping system should be used for supply lines in buildings with concrete
walls? - CORRECT-ANSWERSExposed
(15.) What insulation should be used on high temperature high-pressure steam lines? -
CORRECT-ANSWERSMagnesia insulation
, (16.) Which method should be used when a lavatory is completely stopped up? - CORRECT-
ANSWERSMechanical
(17.) What should be done before removing a section of piping to repair a vertical pipe run? -
CORRECT-ANSWERSSupport and brace
(18.) Plastic WATER service piping shall have a minimum cover of: - CORRECT-ANSWERS12
inches.
(19.) When connecting a larger size pipe to a smaller size pipe use a: - CORRECT-ANSWERSbell
reducer.
(20.) The minimum size water supply line to a flushomatic valve on a water closet is: -
CORRECT-ANSWERS1".
(21.) What is the minimum height the anti-siphon valve on a lawn sprinkler system shall be
above the surrounding ground and above a sufficient number of sprinkler heads? - CORRECT-
ANSWERS6"
(22.) A gallon of water is considered to weigh most nearly: - CORRECT-ANSWERS8.34 lb.
(23.) Which valve gives you the major amount of water during a flushing? - CORRECT-
ANSWERSFlushomatic valve
(24.) Combination pressure and temperature valves shall be installed so that the temperature
sensing element is within ____ of the top of the hot water tank. - CORRECT-ANSWERS6"
SYSTEMS EXAM WITH CORRECT
QUESTIONS AND ANSWERS 2025
(1.) Of the following valves, the one code-approved for a building water service line is the: -
CORRECT-ANSWERSgate valve.
(2.) A water heater must have shut-off valve in the cold water supply line. The valve location
should not exceed _____ feet from the water heater. - CORRECT-ANSWERS3
(3.) A device used to prevent backflow by siphonic action is called a: - CORRECT-
ANSWERSvacuum breaker.
(4.) In a location where higher water pressure is unavailable, how can water line friction loss be
overcome? - CORRECT-ANSWERSBy increasing pipe diameter
(5.) What governs the actual cutting of an opening? - CORRECT-ANSWERSThe type of
material
(6.) The plumber uses a variety of tools to do his job; what are the advantages of using a strap
wrench when installing the lavatory? - CORRECT-ANSWERSIt will not damage the chrome
finish of the pipe
,(7.) What is the purpose of pipe "snaking" in trenches? - CORRECT-ANSWERSThermal
expansion
(8.) The top edge over which water in a receptor can overflow is called the: - CORRECT-
ANSWERSflood level rim.
(9.) Some solder used for copper pipe and fitting is composed of: - CORRECT-ANSWERS95%
tin, 5% antimony.
(10.) When may previously used piping material be reused in a potable water supply system? -
CORRECT-ANSWERSWhen its previous use was for a potable water supply system
(11.) To prevent summer condensation on the outside of a cold water pipe, you should: -
CORRECT-ANSWERSinsulate the pipe.
(12.) What is probably the most reliable method for finding the exact location and depth of a
buried pipe? - CORRECT-ANSWERSProbing
(13.) How should holes be made in a line of wall studs to install a water supply pipe? -
CORRECT-ANSWERSDrill in the center
(14.) What type of piping system should be used for supply lines in buildings with concrete
walls? - CORRECT-ANSWERSExposed
(15.) What insulation should be used on high temperature high-pressure steam lines? -
CORRECT-ANSWERSMagnesia insulation
, (16.) Which method should be used when a lavatory is completely stopped up? - CORRECT-
ANSWERSMechanical
(17.) What should be done before removing a section of piping to repair a vertical pipe run? -
CORRECT-ANSWERSSupport and brace
(18.) Plastic WATER service piping shall have a minimum cover of: - CORRECT-ANSWERS12
inches.
(19.) When connecting a larger size pipe to a smaller size pipe use a: - CORRECT-ANSWERSbell
reducer.
(20.) The minimum size water supply line to a flushomatic valve on a water closet is: -
CORRECT-ANSWERS1".
(21.) What is the minimum height the anti-siphon valve on a lawn sprinkler system shall be
above the surrounding ground and above a sufficient number of sprinkler heads? - CORRECT-
ANSWERS6"
(22.) A gallon of water is considered to weigh most nearly: - CORRECT-ANSWERS8.34 lb.
(23.) Which valve gives you the major amount of water during a flushing? - CORRECT-
ANSWERSFlushomatic valve
(24.) Combination pressure and temperature valves shall be installed so that the temperature
sensing element is within ____ of the top of the hot water tank. - CORRECT-ANSWERS6"
