CR-21 Landscaping and Irrigation Mock Exam With Correct Answers 2026/2027

CR-21 Landscaping and Irrigation Mock Exam With
Correct Answers 2026/2027
1. What is the primary function of a "Backflow Preventer" in an irrigation system?

 A) To increase water pressure for far-reaching sprinklers.

 B) To prevent contaminated water from flowing back into the potable water supply.

 C) To filter out sand and debris.

 D) To regulate the timing of the watering cycle.

 Correct Answer: B. This is a critical safety component required by code to protect
the public water system from fertilizers or chemicals.

2. Which type of soil has the highest water-holding capacity?

 A) Sand.

 B) Silt.

 C) Clay.

 D) Loam.

 Correct Answer: C. Clay particles are the smallest and packed tightly, allowing them
to hold more water than larger sand particles.

3. In irrigation, what does "Static Pressure" refer to?

 A) Pressure when the water is flowing.

 B) Pressure when the water is not moving.

 C) The pressure at the sprinkler head.

 D) The pressure lost due to friction in the pipes.

 Correct Answer: B. Static pressure is measured when all valves are closed and no
water is flowing.

4. What is the standard minimum depth for burial of PVC irrigation mainlines in Arizona?

 A) 6 inches.

 B) 12 inches.

 C) 18 inches.

 D) 24 inches.

 Correct Answer: B. Mainlines (constantly under pressure) generally require 12 inches
of cover, while lateral lines require 8-12 inches depending on local codes.

5. Which plant nutrient is primarily responsible for green, leafy growth?

 A) Phosphorus.

,  B) Potassium.

 C) Nitrogen.

 D) Calcium.

 Correct Answer: C. Nitrogen is the first number in the N-P-K fertilizer ratio and is
essential for chlorophyll production.

6. What is the "Critical Path" in a landscape project schedule?

 A) The most expensive part of the job.

 B) The sequence of tasks that determines the overall project duration.

 C) The walkway designed for foot traffic.

 D) The list of plants to be installed.

 Correct Answer: B. Delaying any task on the critical path will delay the final
completion of the project.

7. A "Double Check Valve" (DCV) assembly is typically used in which scenario?

 A) Low-hazard applications where back-siphonage is unlikely.

 B) Systems using high-pressure pumps.

 C) Drip irrigation for cactus.

 D) When there is a direct connection to a sewage line.

 Correct Answer: A. DCVs are common, but high-hazard systems often require a
Reduced Pressure Zone (RPZ) assembly.

8. Which of the following is an "Evergreen" plant?

 A) Desert Willow.

 B) Arizona Ash.

 C) Oleander.

 D) Palo Verde (in dormant season).

 Correct Answer: C. Oleanders retain their foliage year-round, unlike deciduous trees
that shed leaves in winter.

9. What does "GPM" stand for in irrigation design?

 A) Gallons Per Mile.

 B) Gallons Per Minute.

 C) Gauge Pressure Metric.

 D) Ground Pressure Monitor.

 Correct Answer: B. GPM is the standard unit of measurement for water flow.

, 10. In Arizona landscaping, what is the purpose of "Decomposed Granite" (DG)?

 A) To provide a soft surface for playgrounds.

 B) As a decorative mulch that reduces evaporation and controls weeds.

 C) To kill invasive pests.

 D) To act as a foundation for swimming pools.

 Correct Answer: B. DG is the most common desert mulch used for aesthetics and
water conservation.

11. What is "Evapotranspiration" (ET)?

 A) The process of water freezing in the pipes.

 B) The sum of evaporation from the soil and transpiration from plants.

 C) The speed at which a pump operates.

 D) The chemical reaction of fertilizer in water.

 Correct Answer: B. ET rates help determine how much water an irrigation system
needs to provide to keep plants healthy.

12. Which pipe material is most commonly used for underground lateral irrigation lines?

 A) Galvanized steel.

 B) Copper.

 C) PVC (Polyvinyl Chloride).

 D) Cast iron.

 Correct Answer: C. PVC is preferred for its durability, low cost, and ease of
installation.

13. What is the function of a "Solenoid" on an irrigation valve?

 A) To filter the water.

 B) An electromagnetic coil that opens and closes the valve based on an electrical
signal.

 C) To measure the water flow.

 D) To prevent backflow.

 Correct Answer: B. The solenoid is the interface between the controller and the
hydraulic valve.

14. When installing a tree, the "Root Ball" should be placed:

 A) 6 inches below the surrounding soil grade.

 B) Level with or slightly above the surrounding soil grade.

 C) 12 inches above the surrounding soil grade.