Common Irrigation Problems and What Causes Them
The faults that come up most often with garden irrigation: what usually causes them, what you can safely check yourself, and when it's time to get a repair.
Sprinklers not popping up
Pop-up sprinklers rise on water pressure. If one or more stay down, or barely lift, the cause is usually one of these:
- Low pressure on that zone, often caused by a leak or a broken head elsewhere on the same zone
- Dirt, sand or grass roots jamming the head
- A valve that isn't opening fully
- Too many sprinklers on one zone for the water supply
- A worn seal or spring inside the head
What you can check: run the zone and walk along it. A geyser of water, a soggy patch or water bubbling up near a head points to a leak or a broken head. Clear grass growing over the heads, and if you are comfortable doing so, unscrew the nozzle and rinse its small filter screen.
When to get help: if the whole zone is weak and you can't see a leak, it is usually underground, or a valve problem. See irrigation repairs.
One irrigation zone not working
If one zone doesn't come on but the others do, the controller is usually fine. Common causes:
- A faulty valve solenoid (the small coil on top of the valve)
- A wiring fault between the controller and the valve, often cut during digging, paving or building work
- The zone has no run time in the controller's programme
- A blocked or damaged valve
What you can check: look at the programme on the controller and make sure that station has a run time. Start the zone manually from the controller and listen at the valve box for a click.
When to get help: testing the solenoid and wiring needs a meter, and finding a cut wire can mean tracing it through the garden. If no zones work at all, the problem is more likely the controller or the water supply.
Valve leaking, or the system won't switch off
Water that keeps running when the system should be off, or a valve box that is always wet, usually means:
- Sand or debris stuck in the valve, so it can't close fully
- A torn or worn diaphragm inside the valve
- The valve's manual bleed screw or lever left open
- A solenoid that is loose or stuck
What you can check: close the irrigation's water supply tap to stop the water. Make sure the bleed screw or lever on the valve is closed and the solenoid is screwed in hand-tight.
When to get help: if the valve still lets water through, it needs cleaning, a new diaphragm or replacing. A valve that never closes wastes a lot of water, so it's worth fixing quickly.
Low water pressure
Weak sprays, short throw and dry patches between sprinklers usually come down to:
- A leak somewhere on that zone
- Too many sprinklers on one zone
- The supply tap not fully open, or a blocked filter
- Low pressure on the property's supply, or undersized pipes
- A pump problem, if you water from a borehole or tank
What you can check: open the supply tap fully, clean the filter if there is one, and compare zones. If only one zone is weak, look for a leak on it. If every zone is weak, the supply or pump is more likely.
When to get help: a zone with too many sprinklers can be split in two. See irrigation upgrades.
Controller or timer not working
If nothing comes on at the set times, check the controller first:
- No power: the plug, a tripped circuit or a blown fuse
- A flat backup battery, so the time or programme is lost after a power cut or load shedding
- A rain sensor holding the system off, or left in the bypass position by mistake
- The controller switched to off, or the programme set to the wrong days
What you can check: power, the date and time, the programme, and the rain sensor switch. Don't open the controller's mains wiring yourself.
When to get help: older controllers are often worth replacing with a newer one that is easier to programme and adjust through the seasons.
Dry patches or too much water
Brown patches in a watered area, or soggy spots, usually mean the coverage is wrong:
- Heads tilted, sunk or blocked by grass and plants
- Different types of sprinkler on the same zone, watering at different rates
- Shrubs and trees that have grown into the spray
- The same schedule all year, instead of less water in winter
What you can check: run each zone and watch where the water lands. Straighten and clear heads, and cut back plants in the way.
When to get help: if the layout no longer fits the garden, an irrigation service or an upgrade usually fixes it.
Drip irrigation problems
Drip lines are efficient, but they have their own faults:
- Blocked emitters, especially with hard water or dirty borehole water
- Leaks where the line has been cut by a spade or chewed
- A blocked filter or pressure regulator at the start of the line
- Lines buried too deep or pulled loose
What you can check: run the zone and walk the beds. Look for dry plants along the line and for puddles where water is escaping, and clean the filter.
When to get help: heavily blocked lines are often quicker to replace than to clear.
Can't find the cause? Get it repaired
Free, no-obligation quotes in Pretoria, Centurion and Midrand.
Frequently asked questions
Can I fix irrigation problems myself?
Simple ones, yes: clearing grass from heads, cleaning a nozzle or filter, and checking the controller's power and programme. Leaks underground, valve faults, wiring and pressure problems are usually best left to an irrigation contractor.
Why do my sprinklers stay down on one zone only?
Usually low pressure on that zone, caused by a leak, a broken head or a valve that isn't opening fully. If the problem affects every zone, the water supply or pump is more likely.
How do I stop an irrigation system that won't switch off?
Close the irrigation's water supply tap, then check that the valve's bleed screw is closed and the solenoid is tight. If water still runs, the valve needs cleaning or repairing.
Do you repair irrigation systems in Pretoria?
Yes. Repair enquiries are accepted from Pretoria, Pretoria East, Centurion and Midrand, including systems installed by someone else. Call 012 006 5036 or request a quote.
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