IA Certified Irrigation Technician (CIT) — Questions and Answers

Question 1: Which component controls when and how long an irrigation zone operates?

Pump
Backflow preventer
Controller (Correct answer)
Valve

Correct answer: Controller

The controller acts as the "brain" of an irrigation system, programming the start times, run durations, and days of operation for each zone. It dictates when and for how long the valves open, thereby regulating the water flow to different parts of the landscape.

Question 2: A root barrier or root guard is installed in subsurface drip systems primarily to:

Reduce installation depth requirements
Prevent plant roots from clogging emitters (Correct answer)
Improve water infiltration rates
Increase system pressure

Correct answer: Prevent plant roots from clogging emitters

Root intrusion is a common cause of drip emitter clogging in subsurface systems; physical barriers and chemical treatments help prevent it.

Question 3: A zone fails to activate but others work fine. What is the likely cause?

Low mainline pressure
Controller power failure
Broken solenoid or wire (Correct answer)
Faulty pump relay

Correct answer: Broken solenoid or wire

If only one irrigation zone fails to activate while all other zones function correctly, the most likely cause is a localized electrical issue specific to that zone. This typically points to a broken wire preventing the electrical signal from reaching the valve, or a faulty solenoid on that particular valve that cannot open even if it receives power.

Question 4: Brake horsepower (BHP) of a pump is calculated using which formula?

BHP = Flow (GPM) × TDH / 3,960 × pump efficiency (Correct answer)
BHP = Voltage × Amperage
BHP = TDH × pipe diameter
BHP = Flow (GPM) / pressure (PSI)

Correct answer: BHP = Flow (GPM) × TDH / 3,960 × pump efficiency

BHP = (GPM × TDH) / (3,960 × Ep), where 3,960 converts GPM and feet of head to horsepower and Ep is pump efficiency.

Question 5: What does the term 'precipitation rate' mean for a sprinkler system?

The speed at which the sprinkler rotates
The rate at which water is applied to the landscape, expressed in inches per hour (Correct answer)
The number of gallons per minute delivered by the pump
The operating pressure at the sprinkler head

Correct answer: The rate at which water is applied to the landscape, expressed in inches per hour

Precipitation rate (PR) is the depth of water applied per unit time, typically measured in inches per hour, and determines how fast soil absorbs water.

Question 6: What is 'effective rainfall' in an irrigation context?

Rainfall measured at a weather station
Runoff captured in a retention pond
The portion of rainfall that is stored in the root zone and available for plant use (Correct answer)
Any rainfall exceeding 1 inch

Correct answer: The portion of rainfall that is stored in the root zone and available for plant use

Effective rainfall is the fraction of total rainfall that infiltrates and is retained in the crop root zone for use by plants.

Question 7: An Atmospheric Vacuum Breaker (AVB) must be installed at what position relative to the highest downstream outlet?

Underground in a valve box at the same elevation as the lateral lines
At least 6 inches below the highest downstream outlet
At least 6 inches above the highest downstream outlet (Correct answer)
At the point of connection to the water meter regardless of outlet elevation

Correct answer: At least 6 inches above the highest downstream outlet

AVBs must be installed at least 6 inches above the highest downstream outlet to prevent submersion and ensure the device can open to atmosphere and protect against siphonage.

Question 8: In hot, arid climates, how does the crop coefficient (Kc) of turfgrass typically compare to humid climates?

It may be higher due to greater atmospheric demand and more advective energy (Correct answer)
It is the same regardless of climate
It is lower because plants use less water
It is always exactly 1.0

Correct answer: It may be higher due to greater atmospheric demand and more advective energy

In hot, arid regions, advective heat and higher vapor pressure deficits can push turfgrass Kc values above those measured in humid reference conditions.

Question 9: What is the primary function of an irrigation controller?

To regulate mainline water pressure
To automatically open and close valves according to a programmed schedule (Correct answer)
To measure soil nutrient levels
To filter sediment from irrigation water

Correct answer: To automatically open and close valves according to a programmed schedule

An irrigation controller (timer) operates solenoid valves on a preset schedule, automating the opening and closing of irrigation zones without manual intervention.

Question 10: After completing an irrigation audit, the primary deliverable to the client is typically:

A written report with DU results, water use data, schedule recommendations, and repair priorities (Correct answer)
A new irrigation system installation quote
A pump curve for the existing system
A soil test analysis

Correct answer: A written report with DU results, water use data, schedule recommendations, and repair priorities

An audit report documents findings (DU, flow rates, pressure, scheduling), identifies inefficiencies, and provides prioritized recommendations to improve efficiency.

Question 11: Distribution Uniformity Low Quarter (DU_lq) is calculated by dividing the average of the lowest 25% of catch can readings by:

The highest single reading
The design precipitation rate
The overall average of all catch can readings (Correct answer)
The median reading

Correct answer: The overall average of all catch can readings

DU_lq = (average of lowest 25% catch readings) / (average of all catch readings) × 100%, indicating how uniformly water is distributed.

Question 12: Which WaterSense program label applies specifically to irrigation professionals who demonstrate water-efficient design and management knowledge?

WaterSense Irrigation Partner (IrrigationPro) (Correct answer)
WaterSense Labeled Partner
WaterSense at Work
WaterSense Gold Contractor

Correct answer: WaterSense Irrigation Partner (IrrigationPro)

The EPA WaterSense Irrigation Partner program (formerly IrrigationPro) recognizes irrigation professionals who have passed a qualifying third-party exam, such as the IA Certified Irrigation Technician (CIT) exam.

Question 13: Which certification exam does the Irrigation Association offer that is most focused on landscape irrigation system installation and maintenance?

Certified Landscape Irrigation Auditor (CLIA)
Certified Irrigation Designer (CID)
Certified Irrigation Technician (CIT) (Correct answer)
Certified Agricultural Irrigation Specialist (CAIS)

Correct answer: Certified Irrigation Technician (CIT)

The CIT exam covers installation, maintenance, troubleshooting, and basic design of residential and commercial landscape irrigation systems.

Question 14: Which type of drip emitter is installed directly into the main polyethylene supply line and is used in row crops and vineyards?

Micro-spray head
Button emitter on a stake
Inline emitter (drip tape or in-line drip line) (Correct answer)
Jet emitter

Correct answer: Inline emitter (drip tape or in-line drip line)

Inline drip emitters (drip tape and in-line drip line) are factory-installed inside the tubing and are widely used in agricultural and vineyard applications.

Question 15: What is the purpose of a check valve built into a sprinkler head?

To regulate operating pressure
To prevent low-head drainage after the system shuts off (Correct answer)
To increase throw distance
To filter sediment from nozzles

Correct answer: To prevent low-head drainage after the system shuts off

Integral check valves prevent water from draining out of low-lying heads after irrigation, which wastes water and causes wet spots.

Question 16: If daily ETo is 0.25 inches and the crop coefficient is 0.8, what is the daily crop water use (ETc)?

0.45 inches
0.05 inches
0.20 inches (Correct answer)
0.31 inches

Correct answer: 0.20 inches

ETc = ETo × Kc = 0.25 × 0.8 = 0.20 inches per day.

Question 17: What is backflow in an irrigation system?

Water pressure buildup caused by a closed downstream valve
The reverse flow of water from a non-potable source into the potable water supply (Correct answer)
Water flowing in the intended direction from supply to outlet
The forward flow of water through a check valve assembly

Correct answer: The reverse flow of water from a non-potable source into the potable water supply

Backflow is the unwanted reversal of water flow that can allow contaminants from a non-potable source to enter the clean potable water supply.

Question 18: What is the primary role of evapotranspiration (ET) in irrigation?

To monitor root growth
To measure fertilizer loss
To calculate rainfall
To estimate water needs (Correct answer)

Correct answer: To estimate water needs

Evapotranspiration (ET) is the combined process of water evaporating from the soil surface and transpiring from plant leaves. By measuring or estimating ET, irrigation professionals can accurately determine how much water plants are losing and, consequently, how much water needs to be replaced through irrigation to maintain plant health.

Question 19: What is the recommended minimum operating pressure for most pop-up spray heads to ensure proper trajectory and coverage?

30 PSI (Correct answer)
5 PSI
60 PSI
15 PSI

Correct answer: 30 PSI

Most pop-up spray heads are designed to operate at 30 PSI for optimal nozzle trajectory, throw radius, and distribution uniformity.

Question 20: What is the primary purpose of adjusting irrigation run times seasonally?

To match changing ET demand throughout the growing season (Correct answer)
To increase system pressure
To reduce pump wear
To minimize valve cycling

Correct answer: To match changing ET demand throughout the growing season

Seasonal run-time adjustments ensure applied water matches actual crop or turf ET, which varies significantly from spring through summer to fall.

Question 21: What is the minimum air gap required by most plumbing codes to prevent backflow by siphonage?

Equal to the inside diameter of the supply pipe only
A fixed 6 inches regardless of pipe size
Twice the supply pipe diameter or 1 inch, whichever is greater (Correct answer)
Half the diameter of the supply pipe, minimum 0.5 inch

Correct answer: Twice the supply pipe diameter or 1 inch, whichever is greater

An air gap must be at least twice the inside diameter of the supply pipe or 1 inch minimum, whichever is greater, to reliably prevent back-siphonage.

Question 22: Which factor does NOT directly influence evapotranspiration rates?

Soil pH (Correct answer)
Solar radiation
Relative humidity
Wind speed

Correct answer: Soil pH

Soil pH affects nutrient availability and plant health but is not a direct meteorological driver of evapotranspiration.

Question 23: What is the correct protocol when a backflow prevention assembly fails a field test?

Remove the assembly from service, repair or replace it, retest, and certify before returning it to service (Correct answer)
Document the failure and leave the assembly in service until the next scheduled annual test
Increase downstream pressure temporarily to force the device to achieve a passing reading
Install a second backflow preventer immediately downstream as a redundant backup device

Correct answer: Remove the assembly from service, repair or replace it, retest, and certify before returning it to service

A failed assembly must be immediately taken out of service; after repair or replacement it must be retested by a certified tester and receive a passing certification before being returned to service.

Question 24: Cavitation in a centrifugal pump is caused by:

Over-lubrication of pump bearings
Impeller running at too low a speed
Excessive discharge pressure
Low suction pressure causing liquid to vaporize inside the pump (Correct answer)

Correct answer: Low suction pressure causing liquid to vaporize inside the pump

When suction pressure drops below the liquid's vapor pressure, bubbles form and collapse violently inside the pump, causing noise, vibration, and impeller damage.

Question 25: Which tool is used to test voltage in irrigation controller wiring?

Ohmmeter
Clamp meter
Multimeter (Correct answer)
Wire tracer

Correct answer: Multimeter

A multimeter is the essential tool used to test voltage, current, and resistance in electrical circuits, including irrigation controller wiring. It allows technicians to diagnose electrical issues by checking for proper voltage output from the controller to the valves, ensuring the system receives the necessary power to operate.

Question 26: How frequently should testable backflow prevention assemblies typically be tested according to most water authority requirements?

Annually, and after any repair, modification, or relocation (Correct answer)
Only at time of initial installation and commissioning
Every five years as part of routine plumbing inspection
Every two years or when a pressure drop is detected

Correct answer: Annually, and after any repair, modification, or relocation

Most water authorities require testable backflow prevention assemblies to be tested at least once per year and after any repair, modification, or relocation to confirm continued proper operation.

Question 27: Low-volume irrigation systems, including drip and micro-spray, generally achieve higher application efficiency because they:

Apply water slowly near the root zone, minimizing evaporation and overspray (Correct answer)
Operate at higher pressures than sprinklers
Are easier to install than spray heads
Have larger nozzle openings

Correct answer: Apply water slowly near the root zone, minimizing evaporation and overspray

Low-volume systems deliver water directly at or below the canopy near plant roots, which reduces evaporative and wind-drift losses compared to overhead sprinklers.

Question 28: Schedule efficiency (SE) in irrigation describes:

The number of zones completed per hour
The ratio of gallons applied to gallons metered
How well the irrigation schedule matches actual plant water demand (Correct answer)
The pump motor efficiency rating

Correct answer: How well the irrigation schedule matches actual plant water demand

Schedule efficiency measures how closely the programmed irrigation matches the ET-based water requirement; over-scheduling wastes water and reduces SE.

Question 29: How does compaction affect soil-water-plant relationships?

Reduces infiltration and root development (Correct answer)
Promotes microbial activity
Increases aeration
Improves drainage

Correct answer: Reduces infiltration and root development

Soil compaction decreases the pore space within the soil, making it harder for water to infiltrate and for plant roots to penetrate and grow. This leads to increased runoff, reduced water availability for plants, and stunted root development, negatively impacting plant health and water efficiency.

Question 30: Which regulatory standard requires backflow prevention devices on all irrigation systems connected to potable water supplies in the US?

OSHA 1910
Local plumbing codes (based on ASSE/AWWA standards) (Correct answer)
ASHRAE 90.1
EPA NPDES

Correct answer: Local plumbing codes (based on ASSE/AWWA standards)

Local plumbing codes, typically based on ASSE standards (e.g., ASSE 1013 for reduced pressure principle assemblies) and AWWA guidance, mandate backflow prevention on irrigation connections.

Question 31: Which wireless communication technology is most commonly used for Wi-Fi-connected residential smart irrigation controllers in the US?

Cellular LTE
LoRaWAN
2.4 GHz or 5 GHz Wi-Fi (IEEE 802.11) (Correct answer)
Zigbee 900 MHz

Correct answer: 2.4 GHz or 5 GHz Wi-Fi (IEEE 802.11)

Most residential smart controllers (e.g., Rachio, RainBird ST8I) connect to home Wi-Fi networks using standard 2.4 GHz or 5 GHz IEEE 802.11 protocols for app-based control.

Question 32: Which of the following represents a high-hazard cross-connection in an irrigation system?

A garden hose connected to an outdoor residential spigot
A potable water supply connected to a system with fertilizer injection or recycled water (Correct answer)
An air gap at an atmospheric tank inlet
A pressure-reducing valve installed on the main supply line

Correct answer: A potable water supply connected to a system with fertilizer injection or recycled water

Connecting potable water to systems with chemical injectors or recycled water creates a high-hazard cross-connection due to the serious health risk of contamination.

Question 33: Which irrigation scheduling method uses soil moisture sensors to determine when to irrigate?

Calendar-based scheduling
Checkbook method
Soil water depletion method (Correct answer)
Evaporation pan method

Correct answer: Soil water depletion method

The soil water depletion method uses sensors such as tensiometers or capacitance probes to monitor soil moisture and trigger irrigation at a set threshold.

Question 34: A drip system emitter rated at 1.0 GPH operates for 2 hours. How much water has been applied?

2.0 gallons (Correct answer)
4.0 gallons
1.0 gallon
0.5 gallons

Correct answer: 2.0 gallons

Volume = flow rate × time = 1.0 GPH × 2 hours = 2.0 gallons per emitter.

Question 35: What is a symptom of a short circuit in irrigation valve wiring?

Sprinkler heads not popping up
Controller shows fault or shuts down (Correct answer)
Excessive water pressure
Inconsistent watering schedule

Correct answer: Controller shows fault or shuts down

A short circuit in irrigation valve wiring creates an unintended low-resistance path for electrical current, causing an excessive current draw. This typically triggers the controller's internal protection mechanisms, leading to a fault display, a blown fuse, or the controller shutting down completely to prevent damage to its components.

Question 36: Why is soil texture important in irrigation planning?

It changes root depth
It affects soil temperature
It controls water retention and movement (Correct answer)
It determines fertilizer requirements

Correct answer: It controls water retention and movement

Soil texture, determined by the proportion of sand, silt, and clay, directly influences how well soil retains water and how quickly water moves through it. This knowledge is crucial for setting appropriate irrigation schedules and application rates to prevent water waste and ensure plants receive adequate moisture.

Question 37: What happens when water is applied faster than the soil’s infiltration rate?

It increases crop yield
It enhances deep watering
It causes runoff (Correct answer)
It promotes evaporation

Correct answer: It causes runoff

When water is applied faster than the soil's infiltration rate, the soil cannot absorb it quickly enough, leading to surface runoff. This wastes water, can carry away topsoil and nutrients, and prevents the water from reaching the plant roots effectively.

Question 38: A pressure-compensating (PC) drip emitter maintains a consistent flow rate over a pressure range typically of:

1–5 PSI
50–80 PSI
7–45 PSI (Correct answer)
100–150 PSI

Correct answer: 7–45 PSI

PC emitters use a flexible diaphragm to maintain consistent output, typically between 7 and 45 PSI, which is ideal for sloped terrain.

Question 39: Which system component is used to reduce mainline pressure to the operating pressure required by drip emitters?

Backflow preventer
Filter screen
Air/vacuum relief valve
Pressure regulator (Correct answer)

Correct answer: Pressure regulator

A pressure regulator is installed upstream of the drip zone to reduce domestic or mainline pressure (often 60–80 PSI) to the 20–30 PSI range needed by drip emitters.

Question 40: How does slope affect irrigation efficiency?

Reduces the need for emitters
Causes runoff and uneven watering (Correct answer)
Prevents soil erosion
Improves water retention

Correct answer: Causes runoff and uneven watering

Slope significantly affects irrigation efficiency by causing water to run off downhill before it can adequately infiltrate the soil, especially on steeper grades. This leads to less water reaching plants at the top of the slope and excessive accumulation at the bottom, resulting in uneven watering, wasted water, and potential soil erosion.

Question 41: What is static pressure in an irrigation system?

Pressure during water flow
Lowest pressure in a pipe
Backpressure from pump
Pressure with all valves closed (Correct answer)

Correct answer: Pressure with all valves closed

Static pressure in an irrigation system refers to the pressure of the water when it is at rest, meaning there is no flow. This occurs when all valves are closed, and it represents the maximum potential pressure available from the water source before any dynamic losses from movement begin.

Question 42: A Double Check Valve (DCV) assembly is most appropriate for which type of application?

Low-to-moderate hazard applications where the potential contaminant is not a health threat (Correct answer)
Situations where there is absolutely no risk of back-pressure from the downstream system
High-hazard applications such as chemical or fertilizer injection systems
Locations where maintaining a physical air gap is not structurally possible

Correct answer: Low-to-moderate hazard applications where the potential contaminant is not a health threat

DCVs are suitable for low-to-moderate hazard cross-connections where the potential contaminant would not pose a direct health hazard, such as non-toxic aesthetic contaminants.

Question 43: What is the typical voltage output of a residential irrigation controller?

48V DC
24V AC (Correct answer)
120V AC
12V DC

Correct answer: 24V AC

Residential irrigation controllers typically operate on a low voltage alternating current (AC) for safety and compatibility with standard valve solenoids. The standard output voltage for activating these solenoids is 24 volts AC, which is stepped down from the household 120V AC supply by a transformer within the controller unit.

Question 44: Which factor most directly influences plant water uptake?

Plant color
Air temperature
Root zone moisture (Correct answer)
Leaf size

Correct answer: Root zone moisture

Plants absorb water primarily through their roots, so the amount of moisture available in the root zone directly dictates their water uptake. Insufficient moisture leads to wilting, while excessive moisture can cause root rot, both hindering plant health.

Question 45: A variable frequency drive (VFD) on an irrigation pump motor is used primarily to:

Step up voltage to the motor
Filter electrical noise from the control system
Increase motor starting torque
Adjust pump speed to match system demand and save energy (Correct answer)

Correct answer: Adjust pump speed to match system demand and save energy

A VFD modulates pump speed to maintain a target pressure or flow, reducing energy consumption significantly compared to throttling or cycling.

Question 46: What is the primary advantage of drip irrigation over sprinkler irrigation for shrub beds?

Lower installation cost
Water is delivered directly to the root zone, reducing evaporation and foliar wetting (Correct answer)
Greater throw radius
Higher precipitation rates

Correct answer: Water is delivered directly to the root zone, reducing evaporation and foliar wetting

Drip irrigation delivers water slowly at the root zone, minimizing evaporation, surface runoff, and disease caused by wet foliage.

Question 47: The 'checkbook method' of irrigation scheduling tracks what two primary inputs?

Fertilizer and pH
Rainfall and ET (Correct answer)
Runoff and deep percolation
Temperature and wind

Correct answer: Rainfall and ET

The checkbook method balances rainfall and ET as deposits and withdrawals to maintain soil moisture within an acceptable range.

Question 48: A master valve (MV) in an irrigation system is installed:

At each sprinkler head
On the mainline upstream of all zone valves, and opens only when a station is active (Correct answer)
Inside the controller cabinet
At the well pump discharge

Correct answer: On the mainline upstream of all zone valves, and opens only when a station is active

The master valve is a normally-closed valve on the mainline that the controller opens whenever a station runs; it prevents water waste from valve leaks when the system is off.

Question 49: Which controller program type allows different zones to run on different days of the week?

Single-run program
Interval program (every N days)
Day-of-week program (Correct answer)
Odd/even day program

Correct answer: Day-of-week program

A day-of-week program lets the user assign specific days (e.g., Mon/Wed/Fri) to each zone, providing flexible scheduling aligned with local watering restrictions.

Question 50: What is the significance of the pump curve intersection with the system curve?

It defines the maximum possible pressure
It is the operating point where the pump actually runs in the system (Correct answer)
It shows the cavitation threshold
It represents shutoff head only

Correct answer: It is the operating point where the pump actually runs in the system

The intersection of the pump curve and system curve defines the actual operating flow rate and head for the installed system.

Question 51: An irrigation audit station flow rate is determined by measuring:

Static pressure only
The pipe diameter at the valve
The volume of water discharged from a zone over a measured time period (Correct answer)
The number of heads in the zone

Correct answer: The volume of water discharged from a zone over a measured time period

Station flow rate (GPM) is measured by recording the volume flowing through a meter or bucket test over a timed period while the zone runs.

Question 52: Which scenario would require an RPZ assembly rather than a PVB for irrigation backflow protection?

A residential turf irrigation system supplied entirely by potable city water with no chemical application
A commercial irrigation system supplied by a reclaimed or recycled water source (Correct answer)
A sports field irrigation system using potable water with no fertilizer injection
A small residential drip system irrigating a non-edible ornamental garden

Correct answer: A commercial irrigation system supplied by a reclaimed or recycled water source

Systems connected to reclaimed or recycled water are classified as high-hazard cross-connections and require an RPZ assembly, the highest-rated mechanical backflow protection, per most regulatory codes.

Question 53: A rain sensor on an irrigation controller is designed to:

Increase run times during dry weather
Alert the controller to low-pressure conditions
Measure soil moisture levels
Interrupt or delay scheduled irrigation when sufficient rainfall occurs (Correct answer)

Correct answer: Interrupt or delay scheduled irrigation when sufficient rainfall occurs

Rain sensors interrupt or postpone irrigation when rainfall exceeds a set threshold, preventing unnecessary watering and saving water.

Question 54: What does 'smart controller' mean in the context of WaterSense labeled controllers?

A controller with Bluetooth connectivity
A controller that automatically adjusts schedules based on weather and/or soil moisture data (Correct answer)
A controller that tracks water billing
A controller with a color touchscreen

Correct answer: A controller that automatically adjusts schedules based on weather and/or soil moisture data

EPA WaterSense labeled weather-based controllers adjust irrigation schedules using real-time or historical ET data to avoid over-watering.

Question 55: What causes pressure loss in irrigation pipes?

Elevation gain
Pipe friction and fittings (Correct answer)
Pump horsepower
Temperature change

Correct answer: Pipe friction and fittings

Pressure loss in irrigation pipes is primarily caused by friction between the flowing water and the interior surfaces of the pipes, as well as turbulence and resistance created by fittings like elbows, tees, and valves. This resistance converts some of the water's energy into heat, resulting in a reduction of pressure downstream, known as dynamic pressure loss.

Question 56: Which weather variable has the greatest influence on reference evapotranspiration (ETo) in humid climates?

Relative humidity
Net radiation (Correct answer)
Soil temperature
Wind speed

Correct answer: Net radiation

Net radiation is typically the dominant driver of ETo in humid climates where vapor pressure deficit is lower.

Question 57: During a catch can audit, how many cans are typically placed in a single irrigation zone?

3–4 cans per zone
At least 8–16 cans per zone in a grid pattern (Correct answer)
1–2 cans per zone
One can per sprinkler head

Correct answer: At least 8–16 cans per zone in a grid pattern

IA protocols recommend placing a minimum of 8–16 catch cans in a grid pattern across the zone to capture variability and calculate meaningful DU.

Question 58: What is the minimum acceptable DU_lq percentage recommended by the Irrigation Association for landscape systems?

90%
55%
40%
70% (Correct answer)

Correct answer: 70%

The IA recommends a minimum DU_lq of 70% for landscape sprinkler systems; values below this indicate significant waste or dry spots.

Question 59: Which two pressure conditions can cause backflow to occur?

Back-siphonage and back-pressure (Correct answer)
High flow velocity and low system pressure
Corrosion and pipe failure
High pressure and low flow

Correct answer: Back-siphonage and back-pressure

Backflow is caused by back-siphonage (negative/reduced supply pressure creating a siphon) or back-pressure (downstream pressure exceeding supply pressure).

Question 60: Reference evapotranspiration (ETo) is most commonly calculated using which method recognized by the FAO?

Thornthwaite method
Blaney-Criddle method
Penman-Monteith method (Correct answer)
Hargreaves method

Correct answer: Penman-Monteith method

The FAO-56 Penman-Monteith equation is the globally recognized standard for calculating reference evapotranspiration.

Question 61: What is the Management Allowable Depletion (MAD) typically set at for most turf and landscape irrigation?

50–60%
70–80%
25–40% (Correct answer)
10–20%

Correct answer: 25–40%

MAD for turf and landscape is typically set between 25–40% of plant available water to avoid plant stress.

Question 62: Water hammer in irrigation pipelines is best mitigated by:

Increasing pipe diameter at the pump
Installing check valves on each head
Using slow-closing valves and/or pressure relief valves (Correct answer)
Reducing operating pressure at the controller

Correct answer: Using slow-closing valves and/or pressure relief valves

Slow-closing valves reduce the rate of velocity change that causes pressure transients; pressure relief or surge relief valves absorb residual pressure waves.

Question 63: What happens when irrigation zones are over-pressurized?

Improves uniformity
Boosts sprinkler lifespan
Leads to misting and runoff (Correct answer)
Reduces water usage

Correct answer: Leads to misting and runoff

When irrigation zones are over-pressurized, sprinklers tend to atomize water into a fine mist, which is highly susceptible to wind drift and evaporation, leading to poor distribution uniformity. Additionally, the high application rate can exceed the soil's infiltration capacity, resulting in wasteful runoff and uneven watering across the landscape.

Question 64: In most U.S. jurisdictions, who bears primary legal responsibility for ensuring backflow prevention devices on a private irrigation system are properly installed, tested, and maintained?

The property owner or their authorized representative (Correct answer)
The irrigation contractor who originally installed the system
The state health department or environmental agency
The water utility company serving the property

Correct answer: The property owner or their authorized representative

Property owners bear the legal responsibility for cross-connection control on their premises, including installation, testing, and maintenance of backflow prevention devices, though they hire certified testers to perform the work.

Question 65: Wire-to-water efficiency of a pump system measures overall efficiency from:

Well screen to above-ground discharge
Impeller to discharge nozzle
Electrical power input at the utility meter to hydraulic power delivered to the water (Correct answer)
Motor terminals to pump shaft

Correct answer: Electrical power input at the utility meter to hydraulic power delivered to the water

Wire-to-water efficiency accounts for motor, pump, and any drive system losses—it is the most complete measure of energy performance for an irrigation pump station.

Question 66: Total Dynamic Head (TDH) in a pump system is the sum of which components?

Pump horsepower + motor efficiency
Static head + friction losses + velocity head + pressure head at discharge (Correct answer)
Operating pressure + static water level only
Flow rate + pipe diameter + elevation

Correct answer: Static head + friction losses + velocity head + pressure head at discharge

TDH = static head + friction head losses + velocity head + any pressure required at the point of delivery, representing total energy the pump must supply.

Question 67: A two-wire decoder irrigation system differs from a conventional controller system because:

It uses wireless radio signals only
It uses higher voltage to power the solenoid valves
It runs all field wiring from the controller through a single pair of wires to decoder modules at each valve (Correct answer)
It requires no controller at all

Correct answer: It runs all field wiring from the controller through a single pair of wires to decoder modules at each valve

Two-wire decoder systems replace multi-conductor cables with a single two-wire path carrying both power and communication signals to individual decoder modules at each valve.

Question 68: What does the term 'irrigation interval' refer to?

The number of days between irrigation events (Correct answer)
The pressure loss across a valve
The duration of each watering event
The number of sprinkler heads per zone

Correct answer: The number of days between irrigation events

Irrigation interval is the number of days between scheduled watering events, determined by depletion rate and MAD.

Question 69: An irrigation controller that automatically adjusts run times based on local ET data is called a:

Hydraulic controller
Time-based controller
Interval timer
Smart or ET-based controller (Correct answer)

Correct answer: Smart or ET-based controller

Smart or ET-based controllers use weather data or on-site sensors to continuously adjust irrigation schedules to match actual plant water needs.

Question 70: Which IA exam covers advanced irrigation system design, central control, and large-scale system management?

Certified Irrigation Technician (CIT)
Certified Golf Irrigation Auditor (CGIA) (Correct answer)
Certified Agricultural Irrigation Specialist (CAIS)
Certified Irrigation Designer — Landscape (CID)

Correct answer: Certified Golf Irrigation Auditor (CGIA)

The CGIA credential specifically addresses golf irrigation systems, including advanced central control, pump stations, large-scale scheduling, and water auditing unique to golf course management.

Question 71: Which organization is the primary authority for backflow prevention standards and tester certification in the United States?

U.S. Environmental Protection Agency (EPA)
Occupational Safety and Health Administration (OSHA)
USC Foundation for Cross-Connection Control and Hydraulic Research (USC-FCCC) (Correct answer)
American Backflow Prevention Association (ABPA)

Correct answer: USC Foundation for Cross-Connection Control and Hydraulic Research (USC-FCCC)

The USC Foundation for Cross-Connection Control and Hydraulic Research is widely recognized as the primary authority for backflow prevention standards, device approval, and tester certification programs in the U.S.

Question 72: In a matched precipitation rate (MPR) sprinkler system, what is adjusted to ensure equal precipitation regardless of arc?

Operating pressure
Valve size
Nozzle flow rate (Correct answer)
Head spacing

Correct answer: Nozzle flow rate

MPR nozzles adjust flow rate proportionally to the arc (e.g., a 90° head uses ¼ the flow of a 360° head) so all heads apply the same depth per hour.

Question 73: Landscape water use efficiency (WUE) is expressed as the ratio of:

Plant biomass to water applied
Drip zones to spray zones
Water beneficially used to total water applied (Correct answer)
Evapotranspiration to precipitation

Correct answer: Water beneficially used to total water applied

WUE = beneficial water use / total water applied × 100%; the goal is to maximize plant water use and minimize waste from runoff, deep percolation, and evaporation.

Question 74: Which device measures water flow rate in irrigation systems?

Rain sensor
Pressure regulator
Flow meter (Correct answer)
Valve controller

Correct answer: Flow meter

A flow meter is a specialized device designed to accurately measure the volume of water passing through a pipe over a specific period, thereby indicating the water flow rate. This measurement is crucial for monitoring water usage, detecting leaks, and ensuring the irrigation system operates efficiently according to its design specifications.

Question 75: Distribution uniformity (DU) for a sprinkler system is calculated using data from which type of field test?

Pressure gauge test
Flow meter test
Soil probe test
Catch can test (Correct answer)

Correct answer: Catch can test

A catch can test collects water from multiple locations within a zone to measure application uniformity and calculate DU.

Question 76: A 'common wire' (C or COM) in irrigation wiring connects:

The controller to the pump relay
The rain sensor to the controller
All solenoid valve common terminals back to the controller's common terminal, completing the electrical circuit (Correct answer)
The master valve to each zone valve

Correct answer: All solenoid valve common terminals back to the controller's common terminal, completing the electrical circuit

The common wire is the shared return path for all zone valve solenoids; each solenoid has its own hot wire from the controller and shares the common wire back.

Question 77: Static suction lift is the vertical distance between the:

Pump discharge and the highest sprinkler head
Pump inlet and outlet flanges
Ground surface and the buried mainline
Water surface and the pump centerline when the pump is above the water source (Correct answer)

Correct answer: Water surface and the pump centerline when the pump is above the water source

Static suction lift is the vertical elevation the pump must lift water on the inlet side; atmospheric pressure limits this to approximately 25 feet at sea level.

Question 78: Which type of sprinkler head is best suited for large turf areas such as sports fields and golf courses?

Fixed spray head
Micro-spray head
Bubbler
Rotary or rotor head (Correct answer)

Correct answer: Rotary or rotor head

Rotary (rotor) heads rotate and throw water over large radii, making them efficient for large turf areas with lower precipitation rates.

Question 79: Which instrument is used to directly measure reference evapotranspiration in the field?

Anemometer
Piezometer
Tensiometer
Lysimeter (Correct answer)

Correct answer: Lysimeter

A lysimeter is a precision device that measures actual water use by plants by weighing or monitoring drainage from an isolated soil-plant system.

Question 80: Why is it important to consider soil type in irrigation design?

It dictates sprinkler height
It controls water infiltration and retention (Correct answer)
It changes pipe pressure
It affects plant color

Correct answer: It controls water infiltration and retention

Soil type significantly impacts how quickly water infiltrates the ground and how much moisture it can retain. Understanding this helps in selecting appropriate sprinkler types, application rates, and run times to prevent runoff or underwatering, ensuring efficient water delivery to the plant roots.

Question 81: What should be considered when selecting a sprinkler type for a new landscape?

Soil pH
Color of sprinkler heads
Sunlight intensity
Plant type and area layout (Correct answer)

Correct answer: Plant type and area layout

The choice of sprinkler type (e.g., spray, rotor, drip) depends on the specific plants being watered and the physical layout of the area. Different plants have varying water needs and root depths, and the area's shape and size dictate which sprinkler will provide the most efficient and uniform coverage.

Question 82: In an ET-based smart controller, what is a 'reference ET station'?

A satellite-based pressure monitoring station
A local soil testing laboratory
A weather station or network that provides ET data the controller uses to adjust run times (Correct answer)
The controller itself located at the property entrance

Correct answer: A weather station or network that provides ET data the controller uses to adjust run times

A reference ET station (on-site or remote) measures or calculates ETo data that the smart controller uses to compute and adjust daily irrigation run times.

Question 83: In a water budget approach to irrigation management, the maximum allowed water use (MAW) is based on:

The previous year's water bill
Flat rate per zone
The number of irrigation heads installed
A calculated ET-based water allowance for the landscape area (Correct answer)

Correct answer: A calculated ET-based water allowance for the landscape area

A water budget sets a maximum allowable water use tied to the landscape's ET requirement, incentivizing efficient scheduling to stay within the budget.

Question 84: What does a controller's 'common wire' do?

Activates all valves simultaneously
Powers the rain sensor
Completes the valve circuit (Correct answer)
Connects power to the timer

Correct answer: Completes the valve circuit

The controller's 'common wire' is crucial as it completes the electrical circuit for all irrigation valves. Each valve has a hot wire from its specific zone terminal and a common wire that connects back to a single common terminal on the controller, allowing the electrical current to flow and activate the solenoid when a zone is energized.

Question 85: Back-siphonage in an irrigation system is most likely to occur when:

A sudden high demand or break in the supply main creates negative pressure (Correct answer)
The irrigation system operates at peak design flow rate
A check valve fails to close properly under forward flow
System pressure is significantly higher than normal operating pressure

Correct answer: A sudden high demand or break in the supply main creates negative pressure

Back-siphonage occurs when negative pressure in the supply line draws water backward, commonly caused by high upstream demand, a main break, or firefighting activities.

Question 86: What is 'throw radius' for a rotary sprinkler head?

The rotational speed in RPM
The volume of water discharged per minute
The horizontal distance water travels from the nozzle (Correct answer)
The height the water stream reaches

Correct answer: The horizontal distance water travels from the nozzle

Throw radius is the horizontal distance from the sprinkler head to the farthest point where water reaches the ground at the specified operating pressure.

Question 87: Who is authorized to officially test and certify backflow prevention assemblies?

A certified backflow prevention assembly tester approved by the local water authority or state agency (Correct answer)
Any Irrigation Association Certified Irrigation Technician (CIT)
The irrigation system designer of record for the project
Any licensed plumber holding a journeyman or master license

Correct answer: A certified backflow prevention assembly tester approved by the local water authority or state agency

Only individuals holding a specific backflow prevention assembly tester certification approved by the local water authority or state regulatory agency are authorized to perform official testing and certification.

Question 88: What type of sensor can be wired to a controller's sensor input to automatically suspend irrigation when the soil has sufficient moisture?

UV sensor
Anemometer
Flow meter
Soil moisture sensor (tensiometer or capacitance probe) (Correct answer)

Correct answer: Soil moisture sensor (tensiometer or capacitance probe)

Soil moisture sensors measure water content or soil water tension and can interrupt scheduled irrigation when the soil is already adequately moist.

Question 89: What is the main purpose of a pressure regulator in an irrigation system?

Adjust emitter spacing
Monitor moisture
Control water velocity
Maintain consistent pressure (Correct answer)

Correct answer: Maintain consistent pressure

The main purpose of a pressure regulator in an irrigation system is to reduce and maintain a consistent, optimal water pressure for sprinklers and drip emitters. By stabilizing pressure, it ensures that all components operate at their designed efficiency, preventing issues like misting, uneven distribution, and premature wear caused by fluctuating or excessive pressure.

Question 90: When testing an RPZ assembly, what condition indicates the relief valve is functioning correctly?

The relief valve opens only when supply pressure drops to zero psi
The zone between the check valves is maintained at least 2 psi lower than supply pressure, with the relief valve opening if that differential is lost (Correct answer)
The relief valve opens whenever downstream pressure exceeds supply pressure by any amount
The relief valve remains permanently closed regardless of downstream pressure changes

Correct answer: The zone between the check valves is maintained at least 2 psi lower than supply pressure, with the relief valve opening if that differential is lost

A properly functioning RPZ maintains a reduced pressure zone at least 2 psi below supply pressure; the relief valve opens to vent water if the differential pressure cannot be maintained, indicating a check valve failure.

Question 91: A crop coefficient (Kc) is used to adjust ETo for a specific crop. What does a Kc value of 1.2 indicate?

The crop uses the same amount as reference
The soil is 20% saturated
The crop uses 20% more water than the reference crop (Correct answer)
The crop uses 20% less water than the reference crop

Correct answer: The crop uses 20% more water than the reference crop

A Kc of 1.2 means the actual crop evapotranspiration (ETc) is 20% greater than the reference ETo.

Question 92: What is the formula for calculating the precipitation rate (PR) of a sprinkler system?

PR = Nozzle size × Spacing
PR = Flow (GPM) × Area (sq ft)
PR = [96.3 × Flow (GPM)] / Area (sq ft) (Correct answer)
PR = Pressure (PSI) / Radius (ft)

Correct answer: PR = [96.3 × Flow (GPM)] / Area (sq ft)

The standard formula is PR (in/hr) = (96.3 × GPM) / sq ft, where 96.3 is a unit conversion constant.

Question 93: In a pop-up sprinkler, the term 'pop-up height' refers to:

The operating pressure required to raise the stem
The distance the sprinkler stem extends above ground during operation (Correct answer)
The throw radius at rated pressure
The depth of the buried body

Correct answer: The distance the sprinkler stem extends above ground during operation

Pop-up height is the distance the internal stem rises above the cap during operation; taller grass requires greater pop-up height (e.g., 4 or 6 inches).

Question 94: What term describes the variation in application rates across multiple sprinkler heads in a zone due to hydraulic differences?

Dynamic pressure loss
Coefficient of variation (CV) (Correct answer)
Friction factor
Hydraulic gradient

Correct answer: Coefficient of variation (CV)

The coefficient of variation (CV) quantifies the variability in water output among multiple emission devices; lower CV indicates more uniform distribution.

Question 95: Which controller feature allows a user to temporarily increase or decrease all run times by a percentage without reprogramming each zone?

Seasonal adjust (water budget) percentage (Correct answer)
Master valve override
Rain delay setting
Station delay feature

Correct answer: Seasonal adjust (water budget) percentage

The seasonal adjust or water budget feature multiplies all station run times by a set percentage, allowing quick seasonal changes without editing each station individually.

Question 96: What is a critical factor when spacing sprinkler heads?

System pressure
Sprinkler material
Head-to-head coverage (Correct answer)
Distance from trees

Correct answer: Head-to-head coverage

Head-to-head coverage ensures that the spray from one sprinkler head reaches the next, providing uniform water distribution across the entire irrigated area. This prevents dry spots and overwatered areas, leading to healthier plant growth and efficient water use.

Question 97: What is the purpose of the 'pump start relay' output on an irrigation controller?

To synchronize multiple controllers on the same system
To shut off the pump if pressure drops
To send a low-power signal to a relay that activates the irrigation pump whenever a zone runs (Correct answer)
To start the irrigation program automatically at sunrise

Correct answer: To send a low-power signal to a relay that activates the irrigation pump whenever a zone runs

The pump start relay (PSR) output sends a 24 VAC signal to an external relay, which in turn switches line voltage to the pump motor whenever irrigation is active.

Question 98: What is the purpose of a solenoid in an irrigation valve?

Activates valve operation (Correct answer)
Detects soil moisture
Measures water flow
Regulates water pressure

Correct answer: Activates valve operation

The solenoid is an electromagnetic component within an irrigation valve that receives an electrical signal from the controller. When energized, it creates a magnetic field that moves a plunger, opening a pilot port and allowing water pressure to shift the main diaphragm, thereby activating the valve and permitting water flow to the zone.

Question 99: What does 'smart irrigation month' (July) promote in the United States?

Free irrigation system inspections by municipalities
Awareness of technology and practices that improve irrigation efficiency (Correct answer)
Switching all systems to drip irrigation
Mandatory water rationing

Correct answer: Awareness of technology and practices that improve irrigation efficiency

July is designated Smart Irrigation Month by the Irrigation Association to raise consumer and professional awareness of water-efficient practices and technology.

Question 100: Net Positive Suction Head Available (NPSHa) must always be:

Equal to static suction lift
Equal to total dynamic head
Greater than NPSHr (required) to prevent cavitation (Correct answer)
Less than NPSHr to maximize flow

Correct answer: Greater than NPSHr (required) to prevent cavitation

NPSHa must exceed NPSHr by at least 2–3 feet of safety margin to ensure the pump does not cavitate.

IA Certified Irrigation Technician (CIT)

The Irrigation Association's Certified Irrigation Technician (CIT) exam tests foundational knowledge in basic irrigation principles, electrical systems, and hydraulics required for landscape irrigation installation and maintenance.

100

Questions

180 min

Time Limit

70%

To Pass

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