CR-21 LANDSCAPES AND IRRIGATION |ACTUAL
QUESTIONS AND VERIFIED ANSWERS|BRAND NEW
2026-2027 UPDATE|GRADED A+
Question 1
What thickness in millimeters of pavers is used for residences?
A. .6
B. .5
C. .75
D. 63.5
CORRECT ANSWER
D. 63.5
Brick (paving brick, pavers). Rectangular fired clay brick with typical dimensions of 4
inches x 8 inches x 2.5 inches thick. Available in a range of colors, paving bricks have no
mortar holes and an average strength of approximately 5,000 PSI.
Question 2
What is the length of a standard concrete block including the mortar joint?
A. 8 inches
B. 10 inches
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,C. 12 inches
D. 16 inches
CORRECT ANSWER
D. 16 inches
Sizes are usually given in their nominal dimensions.A unit measuring 7 5/8" wide, 7 5/8"
high, and 15 5/8"long is known as an 8" x 8" x 16" unit. The mortar jointis intended to be
3/8" to fit the modular design basedon a 4" module.
Question 3
When should you seal the bottom of a piece of wood fencing?
A. If water pools under them
B. when within 5 feet of a sprinkler head
C. If there is less than 2 inches of clearance from the ground.
D. If it touches the earth
CORRECT ANSWER
D. If it touches the earth
Question 4
If the boards have to touch the earth, seal the board ends before you install them.
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,Question 5
How is transplant shock avoided?
A. NEED HELP WITH THIS CHOICE
B. Anti transpirants
C. increase water
D. Fertilize
CORRECT ANSWER
B. Anti transpirants
Antitranspirants, also called antidesiccants, are chemicals that reduce the amount of
water plants lose through transpiration. Antitranspirants are useful because excessive
water loss can result in transplant shock. They normally act either to induce closing of
the stomata or to cover the stomata with a water-impermeable coating.
Question 6
A trench has been prepared for a gray water irrigation lines, according to the International
Residential Code, what shall be the minimum depth of the filter material beneath the
perforated line?
Question 7
A. 12 inches
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, B. 3 inches
C. 8 inches
D. 6 inches
CORRECT ANSWER
D. 6 inches
Not less than 6 inches in depth of aggregate, ranging in size from 1/2 to 2-1/2 inches
(12.7 mm to 64 mm), shall be laid into the trench below the distribution piping elevation.
Question 8
A CR-21 licensee may install residential misting systems under what PSI?
Question 9
A. 1000 psi
B. 120 psi
C. 90 psi
D. 500 psi
CORRECT ANSWER
A. 1000 psi
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@THE STUDY VAULT
QUESTIONS AND VERIFIED ANSWERS|BRAND NEW
2026-2027 UPDATE|GRADED A+
Question 1
What thickness in millimeters of pavers is used for residences?
A. .6
B. .5
C. .75
D. 63.5
CORRECT ANSWER
D. 63.5
Brick (paving brick, pavers). Rectangular fired clay brick with typical dimensions of 4
inches x 8 inches x 2.5 inches thick. Available in a range of colors, paving bricks have no
mortar holes and an average strength of approximately 5,000 PSI.
Question 2
What is the length of a standard concrete block including the mortar joint?
A. 8 inches
B. 10 inches
1
@THE STUDY VAULT
,C. 12 inches
D. 16 inches
CORRECT ANSWER
D. 16 inches
Sizes are usually given in their nominal dimensions.A unit measuring 7 5/8" wide, 7 5/8"
high, and 15 5/8"long is known as an 8" x 8" x 16" unit. The mortar jointis intended to be
3/8" to fit the modular design basedon a 4" module.
Question 3
When should you seal the bottom of a piece of wood fencing?
A. If water pools under them
B. when within 5 feet of a sprinkler head
C. If there is less than 2 inches of clearance from the ground.
D. If it touches the earth
CORRECT ANSWER
D. If it touches the earth
Question 4
If the boards have to touch the earth, seal the board ends before you install them.
2
@THE STUDY VAULT
,Question 5
How is transplant shock avoided?
A. NEED HELP WITH THIS CHOICE
B. Anti transpirants
C. increase water
D. Fertilize
CORRECT ANSWER
B. Anti transpirants
Antitranspirants, also called antidesiccants, are chemicals that reduce the amount of
water plants lose through transpiration. Antitranspirants are useful because excessive
water loss can result in transplant shock. They normally act either to induce closing of
the stomata or to cover the stomata with a water-impermeable coating.
Question 6
A trench has been prepared for a gray water irrigation lines, according to the International
Residential Code, what shall be the minimum depth of the filter material beneath the
perforated line?
Question 7
A. 12 inches
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@THE STUDY VAULT
, B. 3 inches
C. 8 inches
D. 6 inches
CORRECT ANSWER
D. 6 inches
Not less than 6 inches in depth of aggregate, ranging in size from 1/2 to 2-1/2 inches
(12.7 mm to 64 mm), shall be laid into the trench below the distribution piping elevation.
Question 8
A CR-21 licensee may install residential misting systems under what PSI?
Question 9
A. 1000 psi
B. 120 psi
C. 90 psi
D. 500 psi
CORRECT ANSWER
A. 1000 psi
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