TEXAS IRRIGATION EXAM| TEXAS LICENSING/CERTIFICATION
EXAM | ALL QUESTIONS AND ANSWERS 2026/2027 | VERIFIED
ANSWERS PLUS RATIONALES | GRADED Q&A
COMPREHENSIVE STUDY GUIDE | VERIFIED LATEST 2027
1. According to Texas administrative rules, what is the minimum bury depth required for
PVC irrigation supply piping installed under residential turf areas to protect against
mechanical damage?
A. 4 inches
B. 6 inches
C. 12 inches
D. 18 inches
Answer: B
Texas Commission on Environmental Quality (TCEQ) rules require a minimum cover of 6 inches
for supply piping to prevent standard residential lawn maintenance equipment from
damaging the system components.
2. A landscape irrigation designer is calculating the total dynamic head (TDH) for a
commercial site utilizing municipal water. The static pressure is 75 PSI, and the elevation
change from the meter to the highest head is a positive 15 feet. What is the pressure loss
due to elevation change alone?
A. 3.25 PSI
B. 6.50 PSI
C. 15.00 PSI
D. 34.60 PSI
Answer: B
Water creates a static pressure change of 0.433 PSI per foot of elevation. Multiplying 15 feet
by 0.433 PSI yields a pressure loss of approximately 6.50 PSI.
3. When installing a backflow prevention assembly on a commercial irrigation system
connected to a potable water supply in Texas, which organization must approve the specific
type of assembly installed?
A. Local homeowner association
B. Texas Department of Transportation
C. TCEQ and the local water purveyor
D. Occupational Safety and Health Administration
,Answer: C
TCEQ regulations and local water purveyors dictate that approved backflow prevention
assemblies, such as Double Check Valve Assemblies or Reduced Pressure Principle Assemblies,
must be utilized to protect public water systems.
4. An irrigation auditor measures an average catch container depth of 0.8 inches and a
lowest quartile catch container depth of 0.6 inches during a scheduled audit. What is the
approximate lower quartile distribution uniformity (DU_lq)?
A. 50 percent
B. 65 percent
C. 75 percent
D. 88 percent
Answer: C
Distribution uniformity using the lower quartile method is calculated by dividing the average
catch depth of the lowest 25 percent by the overall average catch depth (0..8 = 0.75 or 75
percent).
5. Which soil texture classification holds the highest amount of plant-available water per
foot of depth, making it critical to adjust run times to prevent saturation?
A. Coarse sand
B. Loamy sand
C. Silt loam
D. Gravelly coarse sand
Answer: C
Silt loams and medium-textured soils possess a balanced pore space distribution that
maximizes capillary water retention, resulting in high plant-available water holding capacity
compared to coarse sands.
6. A licensed irrigator discovers that a newly installed multi-strand control wire trench
crosses an active high-voltage electrical utility line at a perpendicular angle. What is the
industry best practice regarding separation distance?
A. Touch the lines together for grounding purposes
B. Maintain a minimum vertical and horizontal separation of 12 inches
C. Wrap both cables in the same electrical tape
D. Run the wire directly inside the electric conduit
Answer: B
,Maintaining a minimum 12-inch separation prevents inductive interference, voltage induction
on low-voltage lines, and accidental damage during future utility repairs.
7. What is the primary operational function of a pressure vacuum breaker (PVB) within an
irrigation system design?
A. Protection against back-siphonage only under constant downstream pressure
B. Protection against back-pressure and back-siphonage in non-health hazard conditions
C. Protection against back-siphonage where it is not subjected to continuous pressure for more
than 12 hours out of 24
D. Elimination of water hammer in residential mainline setups
Answer: C
A Pressure Vacuum Breaker is designed to protect against back-siphonage, but it cannot be
subjected to continuous working pressure for more than 12 consecutive hours in a 24-hour
period.
8. When performing solvent welding on PVC irrigation pipe and fittings, what is the
purpose of applying an approved purple primer before laying the cement?
A. To lubricate the pipe for easier insertion into the fitting socket
B. To chemically soften and clean the PVC surface to ensure a molecular bond
C. To act as a permanent waterproof exterior coating
D. To speed up the curing time by cooling the pipe surface
Answer: B
Primer removes grease and softens the rigid PVC resin on both the pipe and fitting socket,
allowing the solvent cement to fuse the two components into a single homogeneous piece of
plastic.
9. A landscape site has a slope of 12 percent across a turf planting bed. Which type of
emission device is most appropriate to prevent excessive runoff and puddling at the bottom
of the slope?
A. High-volume bubblers with no check valves
B. Rotary nozzles with matched precipitation rates and integrated check valves
C. Traditional impact sprinklers operating at high pressure
D. Micro-spray jets with wide fan patterns
Answer: B
Rotary nozzles apply water at a lower precipitation rate, allowing infiltration time on slopes,
while check valves prevent low-head drainage and pooling at the base after the zone turns
off.
, 10. In accordance with Texas water conservation regulations, between what daytime hours
is the operation of automatic lawn irrigation systems generally restricted by many local
municipalities during peak summer months?
A. 12:00 AM to 4:00 AM
B. 5:00 AM to 8:00 AM
C. 10:00 AM to 6:00 PM
D. 8:00 PM to 11:59 PM
Answer: C
Restricting irrigation during peak daylight hours (typically 10:00 AM to 6:00 PM) significantly
minimizes water loss due to high winds and midday evaporation.
11. A homeowner reports that a specific zone valve stays on even after the irrigation
controller display indicates the station is turned off. Upon inspection, the manual bleed
screw is tight. What is the most likely cause of this failure?
A. The controller output fuse is blown
B. Debris is wedged inside the solenoid port or diaphragm, keeping it propped open
C. The common wire has broken off at the valve terminal
D. The rain sensor is actively interrupting the power supply
Answer: B
Small pieces of sand or debris trapped inside the internal bleed passages or under the
diaphragm prevent the valve from sealing shut when solenoid pressure drops.
12. When sizing standard copper or polyethylene tubing for a valve control wire run
exceeding 1,000 feet, what wire gauge is typically required to prevent excessive voltage
drop to the 24VAC solenoid?
A. 18 AWG
B. 14 AWG
C. 22 AWG
D. 26 AWG
Answer: B
Long wire runs experience electrical resistance that lowers voltage at the solenoid; using a
heavier gauge wire like 14 AWG reduces resistance and ensures reliable valve actuation.
13. Which type of backflow prevention assembly utilizes two spring-loaded check valves
and a differential relief valve in the center, and can be installed under continuous pressure
and health hazard applications?
EXAM | ALL QUESTIONS AND ANSWERS 2026/2027 | VERIFIED
ANSWERS PLUS RATIONALES | GRADED Q&A
COMPREHENSIVE STUDY GUIDE | VERIFIED LATEST 2027
1. According to Texas administrative rules, what is the minimum bury depth required for
PVC irrigation supply piping installed under residential turf areas to protect against
mechanical damage?
A. 4 inches
B. 6 inches
C. 12 inches
D. 18 inches
Answer: B
Texas Commission on Environmental Quality (TCEQ) rules require a minimum cover of 6 inches
for supply piping to prevent standard residential lawn maintenance equipment from
damaging the system components.
2. A landscape irrigation designer is calculating the total dynamic head (TDH) for a
commercial site utilizing municipal water. The static pressure is 75 PSI, and the elevation
change from the meter to the highest head is a positive 15 feet. What is the pressure loss
due to elevation change alone?
A. 3.25 PSI
B. 6.50 PSI
C. 15.00 PSI
D. 34.60 PSI
Answer: B
Water creates a static pressure change of 0.433 PSI per foot of elevation. Multiplying 15 feet
by 0.433 PSI yields a pressure loss of approximately 6.50 PSI.
3. When installing a backflow prevention assembly on a commercial irrigation system
connected to a potable water supply in Texas, which organization must approve the specific
type of assembly installed?
A. Local homeowner association
B. Texas Department of Transportation
C. TCEQ and the local water purveyor
D. Occupational Safety and Health Administration
,Answer: C
TCEQ regulations and local water purveyors dictate that approved backflow prevention
assemblies, such as Double Check Valve Assemblies or Reduced Pressure Principle Assemblies,
must be utilized to protect public water systems.
4. An irrigation auditor measures an average catch container depth of 0.8 inches and a
lowest quartile catch container depth of 0.6 inches during a scheduled audit. What is the
approximate lower quartile distribution uniformity (DU_lq)?
A. 50 percent
B. 65 percent
C. 75 percent
D. 88 percent
Answer: C
Distribution uniformity using the lower quartile method is calculated by dividing the average
catch depth of the lowest 25 percent by the overall average catch depth (0..8 = 0.75 or 75
percent).
5. Which soil texture classification holds the highest amount of plant-available water per
foot of depth, making it critical to adjust run times to prevent saturation?
A. Coarse sand
B. Loamy sand
C. Silt loam
D. Gravelly coarse sand
Answer: C
Silt loams and medium-textured soils possess a balanced pore space distribution that
maximizes capillary water retention, resulting in high plant-available water holding capacity
compared to coarse sands.
6. A licensed irrigator discovers that a newly installed multi-strand control wire trench
crosses an active high-voltage electrical utility line at a perpendicular angle. What is the
industry best practice regarding separation distance?
A. Touch the lines together for grounding purposes
B. Maintain a minimum vertical and horizontal separation of 12 inches
C. Wrap both cables in the same electrical tape
D. Run the wire directly inside the electric conduit
Answer: B
,Maintaining a minimum 12-inch separation prevents inductive interference, voltage induction
on low-voltage lines, and accidental damage during future utility repairs.
7. What is the primary operational function of a pressure vacuum breaker (PVB) within an
irrigation system design?
A. Protection against back-siphonage only under constant downstream pressure
B. Protection against back-pressure and back-siphonage in non-health hazard conditions
C. Protection against back-siphonage where it is not subjected to continuous pressure for more
than 12 hours out of 24
D. Elimination of water hammer in residential mainline setups
Answer: C
A Pressure Vacuum Breaker is designed to protect against back-siphonage, but it cannot be
subjected to continuous working pressure for more than 12 consecutive hours in a 24-hour
period.
8. When performing solvent welding on PVC irrigation pipe and fittings, what is the
purpose of applying an approved purple primer before laying the cement?
A. To lubricate the pipe for easier insertion into the fitting socket
B. To chemically soften and clean the PVC surface to ensure a molecular bond
C. To act as a permanent waterproof exterior coating
D. To speed up the curing time by cooling the pipe surface
Answer: B
Primer removes grease and softens the rigid PVC resin on both the pipe and fitting socket,
allowing the solvent cement to fuse the two components into a single homogeneous piece of
plastic.
9. A landscape site has a slope of 12 percent across a turf planting bed. Which type of
emission device is most appropriate to prevent excessive runoff and puddling at the bottom
of the slope?
A. High-volume bubblers with no check valves
B. Rotary nozzles with matched precipitation rates and integrated check valves
C. Traditional impact sprinklers operating at high pressure
D. Micro-spray jets with wide fan patterns
Answer: B
Rotary nozzles apply water at a lower precipitation rate, allowing infiltration time on slopes,
while check valves prevent low-head drainage and pooling at the base after the zone turns
off.
, 10. In accordance with Texas water conservation regulations, between what daytime hours
is the operation of automatic lawn irrigation systems generally restricted by many local
municipalities during peak summer months?
A. 12:00 AM to 4:00 AM
B. 5:00 AM to 8:00 AM
C. 10:00 AM to 6:00 PM
D. 8:00 PM to 11:59 PM
Answer: C
Restricting irrigation during peak daylight hours (typically 10:00 AM to 6:00 PM) significantly
minimizes water loss due to high winds and midday evaporation.
11. A homeowner reports that a specific zone valve stays on even after the irrigation
controller display indicates the station is turned off. Upon inspection, the manual bleed
screw is tight. What is the most likely cause of this failure?
A. The controller output fuse is blown
B. Debris is wedged inside the solenoid port or diaphragm, keeping it propped open
C. The common wire has broken off at the valve terminal
D. The rain sensor is actively interrupting the power supply
Answer: B
Small pieces of sand or debris trapped inside the internal bleed passages or under the
diaphragm prevent the valve from sealing shut when solenoid pressure drops.
12. When sizing standard copper or polyethylene tubing for a valve control wire run
exceeding 1,000 feet, what wire gauge is typically required to prevent excessive voltage
drop to the 24VAC solenoid?
A. 18 AWG
B. 14 AWG
C. 22 AWG
D. 26 AWG
Answer: B
Long wire runs experience electrical resistance that lowers voltage at the solenoid; using a
heavier gauge wire like 14 AWG reduces resistance and ensures reliable valve actuation.
13. Which type of backflow prevention assembly utilizes two spring-loaded check valves
and a differential relief valve in the center, and can be installed under continuous pressure
and health hazard applications?
