North Carolina (NC) Irrigation Contractor Examinations — Level I & II:
200 Practice Questions & Answers
Here is a 200-question practice exam for the North Carolina Irrigation Contractor Examinations
(Level I & II), formatted as a complete study guide with questions, correct answers, and detailed
rationales. The exam is based on the North Carolina General Statutes (GS 89G) , the North
Carolina Administrative Code (Title 21, Chapter 23) , the NCICLB Code of Professional Conduct,
and industry best practices from irrigation design manuals. It is structured to align with the
official NCICLB exam blueprint, covering Water Efficiency/Conservation, Irrigation
Contracting/Construction, Basic Business Skills, and North Carolina Laws & Regulations. The
content is designed to be equally applicable to both Level I and Level II candidates, as the official
exam does not have distinct content variations for the two levels.
Section 1: Water Efficiency & Conservation (Questions 1–50)
QUESTION 1
Which term describes the amount of water applied per hour by a sprinkler head?
A. Precipitation rate
B. Evapotranspiration
C. Infiltration rate
D. Runoff coefficient
Correct Answer: A
Rationale: The precipitation rate is the rate at which water is applied to the soil surface,
expressed in inches per hour. It is a key metric in irrigation design to ensure that the system
applies water at a rate that does not exceed the soil's infiltration capacity.
QUESTION 2
The primary factor that determines a plant's water requirement is:
A. Soil texture only
B. Ambient temperature only
,C. Evapotranspiration (ET)
D. Wind speed only
Correct Answer: C
Rationale: Evapotranspiration (ET) combines water loss from soil evaporation and plant
transpiration and is the key driver of irrigation scheduling. ET is influenced by temperature,
humidity, wind, and solar radiation.
QUESTION 3
Which soil characteristic most directly influences the infiltration rate?
A. Bulk density
B. Organic matter content
C. Particle size distribution
D. Soil pH
Correct Answer: C
Rationale: Particle size distribution (the proportion of sand, silt, and clay) controls pore size and
thus the rate at which water can infiltrate into the soil. Sandy soils have larger pores and faster
infiltration than clay soils.
QUESTION 4
Which type of irrigation system is best suited for narrow planting beds?
A. Large turf areas
B. Sloped landscapes
C. Shrubs and flower beds
D. Sports fields
Correct Answer: C
Rationale: Drip irrigation provides targeted water delivery directly to the root zone, making it
ideal for shrubs, flower beds, and other non-turf planting areas where precision and water
efficiency are priorities.
,QUESTION 5
The purpose of a rain sensor in an irrigation system is to:
A. Measure humidity
B. Control soil pH
C. Shut off irrigation during rainfall
D. Detect leaks
Correct Answer: C
Rationale: Rain sensors conserve water by automatically interrupting the irrigation cycle when a
pre-determined amount of rainfall has occurred. They are a required water conservation device
in many jurisdictions.
QUESTION 6
Which type of grass is most drought-tolerant among the following?
A. Kentucky Bluegrass
B. Bermuda Grass
C. Fescue
D. Ryegrass
Correct Answer: B
Rationale: Bermuda grass is a warm-season grass that tolerates hot, dry conditions much better
than cool-season grasses like Kentucky Bluegrass, Fescue, or Ryegrass. Its drought tolerance
makes it a common choice for lawns in the southern United States.
QUESTION 7
The acceptable Distribution Uniformity (DU) for a residential spray system is generally:
A. ≥ 70%
B. ≥ 50%
, C. ≥ 90%
D. ≥ 30%
Correct Answer: A
Rationale: Distribution Uniformity (DU) is a measure of how evenly water is distributed across
an irrigated area. A DU of 70% or higher is generally considered acceptable for residential spray
systems, ensuring efficient water use and healthy plant growth.
QUESTION 8
A micro‑irrigation system's uniformity is measured by Emission Uniformity (EU). EU is calculated
using:
A. Catch‑can volume data from each emitter
B. Pressure readings at the pump
C. Flow rate of the mainline only
D. Sprinkler spacing charts
Correct Answer: A
Rationale: Emission Uniformity (EU) is the ratio of the average emitter output to the total
output, determined by measuring each emitter's discharge using a catch-can test. This helps
identify clogging or pressure variations in the system.
QUESTION 9
The pressure required for most rotor heads to operate correctly is:
A. 10–20 psi
B. 20–30 psi
C. 30–70 psi
D. 80–120 psi
Correct Answer: C
200 Practice Questions & Answers
Here is a 200-question practice exam for the North Carolina Irrigation Contractor Examinations
(Level I & II), formatted as a complete study guide with questions, correct answers, and detailed
rationales. The exam is based on the North Carolina General Statutes (GS 89G) , the North
Carolina Administrative Code (Title 21, Chapter 23) , the NCICLB Code of Professional Conduct,
and industry best practices from irrigation design manuals. It is structured to align with the
official NCICLB exam blueprint, covering Water Efficiency/Conservation, Irrigation
Contracting/Construction, Basic Business Skills, and North Carolina Laws & Regulations. The
content is designed to be equally applicable to both Level I and Level II candidates, as the official
exam does not have distinct content variations for the two levels.
Section 1: Water Efficiency & Conservation (Questions 1–50)
QUESTION 1
Which term describes the amount of water applied per hour by a sprinkler head?
A. Precipitation rate
B. Evapotranspiration
C. Infiltration rate
D. Runoff coefficient
Correct Answer: A
Rationale: The precipitation rate is the rate at which water is applied to the soil surface,
expressed in inches per hour. It is a key metric in irrigation design to ensure that the system
applies water at a rate that does not exceed the soil's infiltration capacity.
QUESTION 2
The primary factor that determines a plant's water requirement is:
A. Soil texture only
B. Ambient temperature only
,C. Evapotranspiration (ET)
D. Wind speed only
Correct Answer: C
Rationale: Evapotranspiration (ET) combines water loss from soil evaporation and plant
transpiration and is the key driver of irrigation scheduling. ET is influenced by temperature,
humidity, wind, and solar radiation.
QUESTION 3
Which soil characteristic most directly influences the infiltration rate?
A. Bulk density
B. Organic matter content
C. Particle size distribution
D. Soil pH
Correct Answer: C
Rationale: Particle size distribution (the proportion of sand, silt, and clay) controls pore size and
thus the rate at which water can infiltrate into the soil. Sandy soils have larger pores and faster
infiltration than clay soils.
QUESTION 4
Which type of irrigation system is best suited for narrow planting beds?
A. Large turf areas
B. Sloped landscapes
C. Shrubs and flower beds
D. Sports fields
Correct Answer: C
Rationale: Drip irrigation provides targeted water delivery directly to the root zone, making it
ideal for shrubs, flower beds, and other non-turf planting areas where precision and water
efficiency are priorities.
,QUESTION 5
The purpose of a rain sensor in an irrigation system is to:
A. Measure humidity
B. Control soil pH
C. Shut off irrigation during rainfall
D. Detect leaks
Correct Answer: C
Rationale: Rain sensors conserve water by automatically interrupting the irrigation cycle when a
pre-determined amount of rainfall has occurred. They are a required water conservation device
in many jurisdictions.
QUESTION 6
Which type of grass is most drought-tolerant among the following?
A. Kentucky Bluegrass
B. Bermuda Grass
C. Fescue
D. Ryegrass
Correct Answer: B
Rationale: Bermuda grass is a warm-season grass that tolerates hot, dry conditions much better
than cool-season grasses like Kentucky Bluegrass, Fescue, or Ryegrass. Its drought tolerance
makes it a common choice for lawns in the southern United States.
QUESTION 7
The acceptable Distribution Uniformity (DU) for a residential spray system is generally:
A. ≥ 70%
B. ≥ 50%
, C. ≥ 90%
D. ≥ 30%
Correct Answer: A
Rationale: Distribution Uniformity (DU) is a measure of how evenly water is distributed across
an irrigated area. A DU of 70% or higher is generally considered acceptable for residential spray
systems, ensuring efficient water use and healthy plant growth.
QUESTION 8
A micro‑irrigation system's uniformity is measured by Emission Uniformity (EU). EU is calculated
using:
A. Catch‑can volume data from each emitter
B. Pressure readings at the pump
C. Flow rate of the mainline only
D. Sprinkler spacing charts
Correct Answer: A
Rationale: Emission Uniformity (EU) is the ratio of the average emitter output to the total
output, determined by measuring each emitter's discharge using a catch-can test. This helps
identify clogging or pressure variations in the system.
QUESTION 9
The pressure required for most rotor heads to operate correctly is:
A. 10–20 psi
B. 20–30 psi
C. 30–70 psi
D. 80–120 psi
Correct Answer: C
