CR-21 Landscaping and Irrigation: Advanced Practice Exam With Correct Answers 2026/2027

CR-21 Landscaping and Irrigation: Advanced Practice
Exam With Correct Answers 2026/2027

1. What is the primary cause of "Water Hammer" in an irrigation system?

 A) High water temperature.

 B) Air trapped in the pipes or valves closing too quickly.

 C) Using the wrong color of PVC pipe.

 D) Low water pressure at the street.

 Correct Answer: B. A sudden change in water velocity creates a shockwave that can
shatter plastic fittings and damage valves.

2. In Arizona, what is the required minimum depth for a 120V electrical conduit for a
landscape lighting transformer?

 A) 6 inches.

 B) 12 inches.

 C) 18 inches.

 D) 24 inches.

 Correct Answer: C. Per the National Electrical Code (NEC) and most Arizona local
codes, 120V lines in PVC conduit must be buried at least 18 inches deep.

3. What is "Photosynthesis"?

 A) Taking pictures of plants for a portfolio.

 B) The process by which plants use sunlight to synthesize food from carbon dioxide
and water.

 C) The way plants absorb fertilizer through their roots.

 D) A disease caused by too much sun.

 Correct Answer: B. Chlorophyll in the leaves is the key driver of this life-sustaining
process.

4. Which device is used to measure the "Amperage" draw of a solenoid?

 A) Pressure Gauge.

 B) Multimeter.

 C) Tape Measure.

 D) Flow Meter.

 Correct Answer: B. A multimeter helps determine if a solenoid is faulty or if there is
a break in the wire.

,5. What is "Soil Textural Triangle" used for?

 A) Designing a triangular garden.

 B) Determining the classification of soil based on the percentage of sand, silt, and
clay.

 C) Calculating the price of topsoil.

 D) Measuring the depth of a hole.

 Correct Answer: B. It is a standard tool for soil scientists and landscape designers.

6. What is the function of a "Y-Filter" in a drip irrigation system?

 A) To increase the water pressure.

 B) To remove fine sediment and debris that would clog the small openings in
emitters.

 C) To mix fertilizer into the water.

 D) To split the water into two different pipes.

 Correct Answer: B. Because drip emitters have tiny orifices, clean water is
mandatory for system longevity.

7. What does a "3% Grade" signify in site drainage?

 A) The soil is 3% sand.

 B) The ground drops 3 feet in elevation for every 100 feet of horizontal distance.

 C) 3 out of 100 plants will die.

 D) The contractor gets a 3% bonus.

 Correct Answer: B. Proper grading ensures water moves away from building
foundations.

8. Which of these is a "Deciduous" shrub common in Arizona?

 A) Oleander.

 B) Texas Sage.

 C) Pomegranate.

 D) Boxwood.

 Correct Answer: C. Pomegranates lose their leaves in the winter, whereas the others
are largely evergreen in desert climates.

9. What is "Capillary Water"?

 A) Water that flows in a straight line.

 B) Water held in the soil against the force of gravity that is available for plant roots.

 C) Rainwater that stays on the surface.

,  D) Water inside a pump.

 Correct Answer: B. This is the water that plants actually "drink."

10. What is the "Common Wire" in a multi-valve irrigation system?

 A) The wire that everyone uses.

 B) A single wire that connects to one side of every solenoid in the system to
complete the circuit.

 C) The wire that carries the most voltage.

 D) The wire connected to the rain sensor.

 Correct Answer: B. Using a common wire saves a significant amount of cabling
during installation.

11. What is "Pre-Emergent" herbicide?

 A) A chemical used to kill fully grown weeds.

 B) A chemical applied to the soil to prevent weed seeds from germinating.

 C) A type of liquid fertilizer.

 D) A chemical that makes plants grow faster.

 Correct Answer: B. It must be watered in to create a chemical "barrier" in the top
layer of soil.

12. In irrigation design, what is "Dynamic Pressure"?

 A) The pressure when the water is not moving.

 B) The pressure at the source when water is flowing through the system.

 C) The maximum pressure a pipe can hold.

 D) The air pressure inside a tank.

 Correct Answer: B. Also known as "Working Pressure," this determines how far a
sprinkler will spray.

13. What is the purpose of "Teflon Tape" on PVC threads?

 A) To glue the pieces together.

 B) To lubricate the threads and create a watertight seal.

 C) To mark the pipe for future digging.

 D) To prevent the pipe from freezing.

 Correct Answer: B. It should be wrapped in the direction the fitting is tightened.

14. Which nutrient deficiency causes "Interveinal Chlorosis" (yellowing between green veins)?

 A) Nitrogen.