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Texas Landscape Irrigation Exam 2026/2027
Actual Exam | 100% Correct Answers with
Detailed Rationales | Latest Version Expert
Verified | Pass Guaranteed - A+ Graded
Section 1: Hydraulics and Water Management (15 Questions)
Q1: The pressure loss due to friction in an irrigation pipe is affected by:
A. Pipe diameter and length
B. Flow rate
C. Pipe material
D. All of the above [CORRECT]
Correct Answer: D
Rationale: Friction loss is a function of the inside pipe diameter, the length of the pipe, the flow
rate (velocity), and the roughness of the pipe material's interior surface (Hazen-Williams
coefficient).
Q2: When water flows uphill in an irrigation system, the static pressure:
A. Increases
B. Decreases [CORRECT]
C. Remains the same
D. Is converted to velocity
Correct Answer: B
Rationale: For every foot of elevation gain, static pressure decreases by 0.433 PSI. Conversely,
pressure increases when water flows downhill.
,2
Q3: Calculate the precipitation rate (in/hr) for a zone containing 4 spray heads, each using 2.0
GPM, covering a total area of 400 square feet.
A. 1.93 in/hr [CORRECT]
B. 2.50 in/hr
C. 0.50 in/hr
D. 0.02 in/hr
Correct Answer: A
Rationale: The formula for Precipitation Rate is PR = (96.3 × Total GPM) / Area. PR = (96.3 ×
8.0) / 400 = 770. = 1.926 in/hr.
Q4: According to TCEQ regulations and general hydraulic principles, the maximum
recommended water velocity in PVC irrigation mainlines is:
A. 5 feet per second (fps)
B. 7.5 feet per second (fps) [CORRECT]
C. 10 feet per second (fps)
D. 15 feet per second (fps)
Correct Answer: B
Rationale: To prevent water hammer and surge damage, velocity in mainlines should not exceed
7.5 fps. Lateral lines are typically limited to 5 fps.
Q5: If a pressure gauge reads 50 PSI at the Point of Connection (POC) and there is a 15 PSI
pressure loss through the meter, backflow preventer, and mainline, what is the available working
pressure at the valve?
A. 65 PSI
B. 50 PSI
C. 35 PSI [CORRECT]
D. 15 PSI
,3
Correct Answer: C
Rationale: Working pressure is determined by subtracting all friction losses from the static
pressure source. 50 PSI (Static) - 15 PSI (Loss) = 35 PSI (Dynamic/Working Pressure).
Q6: Which of the following pipe sizes has the greatest flow capacity if all are Schedule 40 PVC?
A. 1/2 inch
B. 3/4 inch
C. 1 inch [CORRECT]
D. 1/2 inch Copper
Correct Answer: C
Rationale: Flow capacity is primarily determined by the cross-sectional area of the pipe. A 1-inch
pipe has a significantly larger internal area than 1/2 or 3/4 inch pipes, allowing for higher flow
rates with lower friction loss.
Q7: Static water pressure is defined as:
A. Pressure measured while water is flowing
B. Pressure measured when water is not moving [CORRECT]
C. Pressure loss due to friction
D. Pressure required to operate a sprinkler
Correct Answer: B
Rationale: Static pressure is the pressure exerted by water at rest (no flow). Dynamic (or
working) pressure is the pressure measured while water is flowing and accounts for friction
losses.
Q8: A "pressure vacuum breaker" (PVB) must be installed:
A. At any elevation relative to the sprinklers
, 4
B. At least 12 inches above the highest downstream outlet [CORRECT]
C. Below ground in a vault
D. At the lowest point of the system
Correct Answer: B
Rationale: A PVB is an atmospheric vacuum breaker. It relies on an air inlet to break the vacuum.
To function correctly and prevent back-siphonage, it must be installed a minimum of 12 inches
above the highest sprinkler head or outlet downstream.
Q9: The Hazen-Williams formula is used to calculate:
A. Precipitation rate
B. Friction loss in pipes [CORRECT]
C. Soil infiltration rate
D. Water hammer duration
Correct Answer: B
Rationale: The Hazen-Williams formula is the industry standard empirical formula used to
calculate pressure loss due to water friction inside a pipe based on flow rate, pipe diameter, and a
roughness coefficient (C-factor).
Q10: An irrigation system is designed to operate at 40 PSI. If the sprinkler heads require a
minimum of 30 PSI to operate effectively and the friction loss through the zone valve and lateral
piping is 8 PSI, what is the total pressure required at the valve inlet?
A. 30 PSI
B. 38 PSI [CORRECT]
C. 48 PSI
D. 40 PSI
Correct Answer: B
Texas Landscape Irrigation Exam 2026/2027
Actual Exam | 100% Correct Answers with
Detailed Rationales | Latest Version Expert
Verified | Pass Guaranteed - A+ Graded
Section 1: Hydraulics and Water Management (15 Questions)
Q1: The pressure loss due to friction in an irrigation pipe is affected by:
A. Pipe diameter and length
B. Flow rate
C. Pipe material
D. All of the above [CORRECT]
Correct Answer: D
Rationale: Friction loss is a function of the inside pipe diameter, the length of the pipe, the flow
rate (velocity), and the roughness of the pipe material's interior surface (Hazen-Williams
coefficient).
Q2: When water flows uphill in an irrigation system, the static pressure:
A. Increases
B. Decreases [CORRECT]
C. Remains the same
D. Is converted to velocity
Correct Answer: B
Rationale: For every foot of elevation gain, static pressure decreases by 0.433 PSI. Conversely,
pressure increases when water flows downhill.
,2
Q3: Calculate the precipitation rate (in/hr) for a zone containing 4 spray heads, each using 2.0
GPM, covering a total area of 400 square feet.
A. 1.93 in/hr [CORRECT]
B. 2.50 in/hr
C. 0.50 in/hr
D. 0.02 in/hr
Correct Answer: A
Rationale: The formula for Precipitation Rate is PR = (96.3 × Total GPM) / Area. PR = (96.3 ×
8.0) / 400 = 770. = 1.926 in/hr.
Q4: According to TCEQ regulations and general hydraulic principles, the maximum
recommended water velocity in PVC irrigation mainlines is:
A. 5 feet per second (fps)
B. 7.5 feet per second (fps) [CORRECT]
C. 10 feet per second (fps)
D. 15 feet per second (fps)
Correct Answer: B
Rationale: To prevent water hammer and surge damage, velocity in mainlines should not exceed
7.5 fps. Lateral lines are typically limited to 5 fps.
Q5: If a pressure gauge reads 50 PSI at the Point of Connection (POC) and there is a 15 PSI
pressure loss through the meter, backflow preventer, and mainline, what is the available working
pressure at the valve?
A. 65 PSI
B. 50 PSI
C. 35 PSI [CORRECT]
D. 15 PSI
,3
Correct Answer: C
Rationale: Working pressure is determined by subtracting all friction losses from the static
pressure source. 50 PSI (Static) - 15 PSI (Loss) = 35 PSI (Dynamic/Working Pressure).
Q6: Which of the following pipe sizes has the greatest flow capacity if all are Schedule 40 PVC?
A. 1/2 inch
B. 3/4 inch
C. 1 inch [CORRECT]
D. 1/2 inch Copper
Correct Answer: C
Rationale: Flow capacity is primarily determined by the cross-sectional area of the pipe. A 1-inch
pipe has a significantly larger internal area than 1/2 or 3/4 inch pipes, allowing for higher flow
rates with lower friction loss.
Q7: Static water pressure is defined as:
A. Pressure measured while water is flowing
B. Pressure measured when water is not moving [CORRECT]
C. Pressure loss due to friction
D. Pressure required to operate a sprinkler
Correct Answer: B
Rationale: Static pressure is the pressure exerted by water at rest (no flow). Dynamic (or
working) pressure is the pressure measured while water is flowing and accounts for friction
losses.
Q8: A "pressure vacuum breaker" (PVB) must be installed:
A. At any elevation relative to the sprinklers
, 4
B. At least 12 inches above the highest downstream outlet [CORRECT]
C. Below ground in a vault
D. At the lowest point of the system
Correct Answer: B
Rationale: A PVB is an atmospheric vacuum breaker. It relies on an air inlet to break the vacuum.
To function correctly and prevent back-siphonage, it must be installed a minimum of 12 inches
above the highest sprinkler head or outlet downstream.
Q9: The Hazen-Williams formula is used to calculate:
A. Precipitation rate
B. Friction loss in pipes [CORRECT]
C. Soil infiltration rate
D. Water hammer duration
Correct Answer: B
Rationale: The Hazen-Williams formula is the industry standard empirical formula used to
calculate pressure loss due to water friction inside a pipe based on flow rate, pipe diameter, and a
roughness coefficient (C-factor).
Q10: An irrigation system is designed to operate at 40 PSI. If the sprinkler heads require a
minimum of 30 PSI to operate effectively and the friction loss through the zone valve and lateral
piping is 8 PSI, what is the total pressure required at the valve inlet?
A. 30 PSI
B. 38 PSI [CORRECT]
C. 48 PSI
D. 40 PSI
Correct Answer: B
