22 Installation Practice Questions & Answers

1. 1. While installing to a supplied design, a technician finds the plan drawing calls for a 2-inch mainline but the written specifications require 2.5-inch pipe. Which document governs?

   • A.The specifications govern; the technician reports the conflict to the designer.✓ Answer
   • B.The plan drawing governs; scaled drawings outrank the written documents.
   • C.Local code governs; the technician installs whatever the inspector prefers.
   • D.Neither governs; the technician picks the size the local supplier has in stock.

   In construction documents the written specifications control over the drawings when the two conflict, because the specs state the required quality and materials while the drawing shows arrangement. The technician installs to the specification and documents the discrepancy for the designer rather than choosing on his own.

   Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — installing to plans and specificationsReport a problem with this question

2. 2. Trenching reveals an old concrete footing exactly where the plan routes the mainline. What should the technician do?

   • A.Stop, notify the designer or owner, and install only the change they approve.✓ Answer
   • B.Delete that run of mainline and connect the zone to the nearest lateral instead.
   • C.Reroute the line on his own judgment and say nothing, since the zone still works.
   • D.Bury the mainline shallower over the footing and hold the same routing.

   The technician installs the system someone else designed and does not redesign it in the field; a change forced by an unforeseen site condition needs the designer's or owner's documented approval so hydraulics, coverage and the as-built stay consistent. Burying the line shallower would also leave it exposed to frost and traffic loads.

   Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — field changes and documented deviations from designReport a problem with this question

3. 3. What is the first field step before any trenching or plowing begins on the site?

   • A.Call the one-call underground locate service and wait for the site marks.✓ Answer
   • B.Set all valve boxes so trench depth can be measured from their lids.
   • C.Pressure-test the existing water service to confirm its static reading.
   • D.Stake every head location, then run the trencher along the mainline route.

   Existing utilities must be located and marked before excavation because striking a gas, electric or communication line can kill someone and is the installer's liability. The locate request is made through the one-call service and the legally required wait time must elapse before digging starts.

   Source: Common Ground Alliance one-call (811) damage-prevention practice; Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — excavation safetyReport a problem with this question

4. 4. In a system built to a supplied design, what distinguishes the mainline from the lateral lines once the system is in service?

   • A.The laterals hold pressure at all times, while the mainline fills only while a zone runs.
   • B.Neither holds pressure between cycles, because the master valve drains them after each cycle.
   • C.The mainline holds pressure up to the zone valves; a lateral is pressurized only while its zone runs.✓ Answer
   • D.Both hold pressure continuously, which is why the plan buries them at the same depth.

   The mainline runs from the point of connection and backflow assembly to the remote-control valves and stays under constant pressure, so it is normally installed deeper and tested more rigorously. Everything downstream of a zone valve is lateral pipe, which sees pressure only when that station is energized.

   Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — mainline and lateral pipingReport a problem with this question

5. 5. Working from the city main toward the sprinklers, which sequence matches a standard installation to plan?

   • A.Isolation valve, meter, mainline, backflow assembly, lateral, zone valve, head
   • B.Meter, mainline, isolation valve, zone valve, backflow assembly, lateral, head
   • C.Meter, isolation valve, backflow assembly, mainline, zone valve, lateral, head✓ Answer
   • D.Meter, backflow assembly, isolation valve, lateral, zone valve, mainline, head

   The isolation valve sits just downstream of the meter so the whole irrigation system can be shut off without the building, and the backflow assembly must protect the potable supply before any irrigation piping. Only after the backflow assembly does pressurized mainline reach the zone valves, and lateral pipe with heads follows each valve.

   Source: Irrigation Association, Irrigation Components: Residential/Small Commercial Systems Student Workbook — point of connection and system layoutReport a problem with this question

6. 6. The design routes a lateral and its control wire under a concrete driveway. How is that crossing installed?

   • A.Sleeve pipe at least two nominal sizes larger than the carrier pipe, wire in its own sleeve.✓ Answer
   • B.No sleeve at all, provided the pipe under the drive is buried deeper than elsewhere.
   • C.Sleeve pipe of the same nominal size as the carrier pipe, with the wire pulled in beside it.
   • D.Sleeve pipe one nominal size smaller, so the carrier pipe is gripped against movement.

   A sleeve must be large enough that the carrier pipe can be pulled through and later replaced without breaking the hardscape, which is why it is sized well above the carrier size. Wire is sleeved separately so a wire pull or repair does not disturb the pipe under the pavement.

   Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — sleeving under hardscapeReport a problem with this question

7. 7. The mainline is assembled and the solvent-weld joints have cured. What is correct practice before the trench is closed?

   • A.Wait until the heads are installed, then test the mainline and laterals together.
   • B.Backfill and compact first, then pressurize so the pipe is supported under test.
   • C.Pressurize the mainline with the joints exposed and walk the trench for leaks.✓ Answer
   • D.Test only if an inspector asks, because cured solvent-weld joints rarely leak.

   The mainline is pressure-tested with joints exposed so a weeping fitting can be seen and repaired without re-excavating compacted trench. Backfilling first hides small leaks that will later surface as wet spots and lost water.

   Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — pressure testing before backfillReport a problem with this question

8. 8. Why must each lateral be flushed with its ends open before nozzles and heads are installed?

   • A.Installing the heads first would make it impossible to flush the mainline at all.
   • B.Grit and plastic shavings left in the pipe would clog nozzles and foul diaphragms.✓ Answer
   • C.Water standing in the lateral would slow the cure of the solvent-weld joints.
   • D.Flushing with the heads installed would push the lateral past its pressure rating.

   Cutting, deburring and trenching leave shavings and soil inside the pipe, and the only way out is an open end. Once nozzles are in place the debris has nowhere to go and lodges in nozzle orifices, screens and valve diaphragms, which is why the flush cannot be done after the heads go on.

   Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — flushing laterals prior to head installationReport a problem with this question

9. 9. What does primer do in a PVC solvent-weld joint made during installation?

   • A.It seals the pipe wall so the cement is not absorbed into the plastic surface.
   • B.It softens the surfaces of pipe and socket so the cement can fuse them together.✓ Answer
   • C.It lubricates the socket so the pipe can be pushed fully home before it sets.
   • D.It cleans away dirt and grease so the cement can grip the outside of the pipe.

   A solvent-weld joint is a chemical fusion, not an adhesive bond: primer dissolves and softens the PVC so the cement can weld the two softened surfaces into a single piece of plastic. Skipping primer because it is mistaken for a cleaner is a leading cause of joints that fail under pressure.

   Source: ASTM D2855, Practice for the Two-Step (Primer and Solvent Cement) Method of Joining PVC Pipe and FittingsReport a problem with this question

10. 10. While staking heads to the supplied layout, the technician finds one spray head would land inside an existing tree well. What is the correct response?

    • A.Delete that head and let the two adjacent heads cover the resulting gap.
    • B.Stretch the spacing along that row until the head clears the tree well.
    • C.Hold the design spacing and ask the designer where to relocate that head.✓ Answer
    • D.Add an extra head on the zone with a much larger nozzle to fill the gap.

    Head spacing is what produces uniform coverage, so stretching spacing or deleting a head creates dry areas the design was drawn to avoid. Adding an oversized nozzle also breaks matched precipitation rate across the zone, so the obstruction is reported and the relocation is approved by the designer.

    Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — head layout, spacing and matched precipitation rateReport a problem with this question

11. 11. What does a swing joint under a turf rotor accomplish?

    • A.It raises the operating pressure at the head by smoothing the flow into the inlet.
    • B.It lets the head be set to final grade and absorbs impact loads off the lateral.✓ Answer
    • C.It shortens installation time by removing the need to thread the head onto pipe.
    • D.It strains the grit out of the lateral before the water reaches the head's nozzle.

    The articulating nipples and ells let the head be raised, lowered and squared to finished grade after backfill and settling. They also flex when a mower or vehicle strikes the head, so the impact is absorbed instead of cracking the fitting or the lateral pipe.

    Source: Irrigation Association, Irrigation Components: Residential/Small Commercial Systems Student Workbook — swing joints and head connectionsReport a problem with this question

12. 12. A rotor is left standing an inch above finished grade and leaning toward the turf. Why is that unacceptable?

    • A.It is a mowing and trip hazard, and the tilt throws the pattern off target.✓ Answer
    • B.It raises the zone's operating pressure and makes the zone valve seep water.
    • C.It voids the swing joint warranty, though the coverage pattern is unaffected.
    • D.It adds friction loss in the lateral and lowers the flow reaching the zone.

    A head set proud of grade is struck by mowers and is a trip hazard, and a tilted head aims its arc at an angle so water lands short on one side and overthrows on the other. Heads are set plumb and flush with finished grade so the pattern matches the coverage the design assumed.

    Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — setting heads plumb and to finished gradeReport a problem with this question

13. 13. How are the remote-control valves and their boxes set on an installation built to plan?

    • A.Above grade on a concrete pad, with several valves grouped in one box.
    • B.About two inches below grade and covered with soil so the lid stays hidden.
    • C.Flush with grade but packed with soil inside to support the valve body.
    • D.Flush with finished grade over a gravel base, with one valve per box.✓ Answer

    A box set flush over drainage rock keeps the valve findable, keeps water out of the box and lets the bonnet, solenoid and diaphragm be serviced without cutting pipe. Burying the box or filling it with soil makes routine service a digging job and lets grit into the valve when it is opened.

    Source: Irrigation Association, Irrigation Components: Residential/Small Commercial Systems Student Workbook — valve and valve box installationReport a problem with this question

14. 14. How must the underground control-wire splices at the valves be made?

    • A.With soldered joints coated in primer and left open inside the valve box.
    • B.With twist-on wire nuts wrapped in two full layers of vinyl electrical tape.
    • C.With waterproof connectors listed for direct burial in irrigation splices.✓ Answer
    • D.With crimped sleeves buried in the trench, the ends taped and then painted.

    Buried splices sit in wet soil, and moisture wicking into a taped or bare connection corrodes the copper until the station reads as an open circuit. Only gel-filled or grease-cap connectors listed for direct burial seal the conductor well enough to survive underground.

    Source: Irrigation Association, Electrical Troubleshooting Student Workbook — direct-burial wire splicesReport a problem with this question

15. 15. Why is a loop of slack control wire left at each valve and at changes of direction?

    • A.So the wire can shift with the soil and be pulled up again for later repairs.✓ Answer
    • B.So a lightning strike near the valve has a direct path straight to earth ground.
    • C.So the added wire length raises the voltage that reaches the solenoid coil.
    • D.So the circuit keeps enough resistance to protect the controller's output board.

    Soil settles, heaves and shifts, and wire pulled tight between fixed points eventually breaks at the splice or the fitting. The expansion loop gives the run slack to move and gives a technician enough conductor to cut back and re-splice without pulling new wire.

    Source: Irrigation Association, Electrical Troubleshooting Student Workbook — field wiring practicesReport a problem with this question

16. 16. The field wires have been landed on the controller and the transformer is connected. What must be verified against the supplied design at commissioning?

    • A.That the transformer's output at the terminals measures full line voltage.
    • B.That the common wire is landed on the earth ground rod at the controller.
    • C.That all stations share one hot wire and each valve gets its own common.
    • D.That each station number on the controller runs the zone the plan assigns.✓ Answer

    Station numbering on the controller must match the zone numbering on the design, or every later schedule change and every service call is made against the wrong zone. The technician runs each station manually and confirms the zone that comes on is the one the plan assigns to that number, correcting the wiring or the record before leaving.

    Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — controller hookup and system start-upReport a problem with this question

17. 17. At the point of connection a gauge on a hose bib reads 65 psi with no water moving and 48 psi while a zone is flowing. How should the technician record these readings?

    • A.Both readings are dynamic, since a gauge cannot register a no-flow pressure.
    • B.48 psi is the static reading and 65 psi is dynamic; the gap is meter error.
    • C.Both readings are static, because pressure changes only with elevation change.
    • D.65 psi is static, 48 psi is dynamic, and the drop is loss under flow.✓ Answer

    Static pressure is measured with no water moving; dynamic or working pressure is measured while water flows, and it is always lower because friction in the service line, meter and backflow assembly consumes pressure once there is flow. The difference between the two readings is what the installer compares against the pressure the design assumed.

    Source: Irrigation Association, Basic Irrigation Hydraulics Student Workbook — static and dynamic pressureReport a problem with this question

18. 18. The design is based on 30 gpm at 65 psi at the point of connection, but the technician measures 18 gpm at 45 psi before work begins. What is the correct action?

    • A.Install exactly as drawn and let the owner shorten the run times later on.
    • B.Split each zone across two valves so the available flow feeds half at a time.
    • C.Increase every lateral one pipe size in the field to restore the design flow.
    • D.Record the readings and notify the designer before installing to the plan.✓ Answer

    Every zone on the plan was sized around the supply the designer assumed, so a supply this far below it will leave heads short of their operating pressure no matter how the pipe is installed. Verifying pressure and flow is a pre-installation step precisely so the shortfall is documented and resolved by the designer before pipe goes in the ground.

    Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — verifying site pressure and flow against the designReport a problem with this question

19. 19. A drip zone is being assembled to the plan. Which arrangement downstream of the mainline is correct?

    • A.Filter, then zone valve, then pressure regulator, with no flush point required.
    • B.Zone valve, then pressure regulator, then filter, with the run capped at the end.
    • C.Pressure regulator, then zone valve, then filter, with the end left open in soil.
    • D.Zone valve, then filter, then pressure regulator, with a flush point at the end.✓ Answer

    The filter belongs immediately downstream of the zone valve so that particles shed by the valve and the mainline are caught before they reach the emitters, and the regulator follows the filter so the dripline sees the low pressure it is built for. A flush point at the end of each run lets the line be purged of the fines that always work through, which is why the end is not simply capped.

    Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — drip/micro-irrigation zone assemblyReport a problem with this question

20. 20. Water is about to be admitted to the newly installed mainline for the first time. How should the supply be opened?

    • A.While two zones are running, so the mainline never reaches full pressure.
    • B.Slowly, so the column of water filling the pipe does not slam the system.✓ Answer
    • C.Fully and all at once, so the trapped air is driven out of the pipe fast.
    • D.Only after every head is set, so the mainline and laterals fill together.

    An empty line fills with a fast-moving column of water that stops abruptly at the first closed valve or dead end, and that sudden stop is water hammer, a pressure spike that can split fittings and damage valves. Opening the supply slowly keeps velocity low while air is expelled and the line comes up to pressure.

    Source: Irrigation Association, Basic Irrigation Hydraulics Student Workbook — water hammer and system chargingReport a problem with this question

21. 21. During the operational test of each zone, a corner spray head is throwing water across the sidewalk. What is the correct field response?

    • A.Cap that head and let the neighbouring heads cover the corner between them.
    • B.Adjust the arc and radius at that head so the pattern stays in the design area.✓ Answer
    • C.Replace that spray body with a rotor so the corner is thrown a shorter distance.
    • D.Throttle the zone valve's flow control until that head no longer reaches the walk.

    Arc and radius adjustment at the head is the intended way to trim a pattern to the planted area during the operational test. Throttling the zone valve lowers pressure at every head on the station, and swapping in a rotor destroys matched precipitation rate on a spray zone, so both fixes create a bigger problem than the overspray.

    Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — system start-up, arc and radius adjustmentReport a problem with this question

22. 22. What belongs on the as-built record handed to the owner at close-out, and why does it matter?

    • A.Actual installed positions of valves, splices and sleeves, for later servicing.✓ Answer
    • B.Warranty cards for every head installed, so parts can be claimed without receipts.
    • C.Labour hours and material counts, so the owner can check the final invoice.
    • D.The designer's original dimensions only, since the plan is the contract document.

    Buried components can only be found later from an accurate record of where they actually went in, which is why the as-built shows measured locations of valve boxes, wire splices, sleeves and any routing that differs from the drawing. Without it, the next technician has to locate valves and wire electronically or dig, at the owner's cost.

    Source: Irrigation Association, Landscape Irrigation System Installation & Maintenance, 2nd ed. — as-built documentation and owner turnoverReport a problem with this question

Practice questions based on the Irrigation Association's published Certified Irrigation Technician content — basic irrigation principles, basic electrical principles and basic hydraulics — together with standard irrigation installation, hydraulics and backflow-prevention references. This site is not affiliated with or endorsed by the Irrigation Association. Irrigation work is governed by local plumbing and irrigation codes, water-purveyor rules and licensing that vary by jurisdiction; backflow assemblies in particular must be selected, installed and tested to the rules in force where you work. Confirm current exam requirements with the Irrigation Association before testing. About IA certification →