Short Answer
An irrigation system should be serviced at least once a year, and ideally twice — once in spring to start the system up and once in autumn to shut it down for winter. Systems on large gardens, estates or commercial sites benefit from an additional mid-season check.
Why regular servicing matters
Irrigation systems work outdoors, underground and in all weathers. Over a season, nozzles can become blocked, sprinkler heads can shift, valves can leak, and controllers can lose their programming. A system that is not serviced will gradually become less efficient — watering unevenly, wasting water and eventually failing in ways that are more expensive to fix than a routine service.
The annual service cycle
Spring start-up (March–April)
The spring start-up prepares the system for the growing season:
- Reopen the water supply slowly to avoid pressure surges
- Flush each zone to clear debris from lines and sprinklers
- Check every sprinkler for correct arc, rotation and coverage
- Clean or replace blocked nozzles
- Reprogramme the controller for the season
- Test the rain sensor and any soil-moisture sensors
- Check the pump (if fitted) for pressure and flow
- Inspect valves for leaks
Mid-season check (June–July)
For large gardens and estates, a mid-season check catches problems before they cause damage:
- Verify coverage during peak demand
- Adjust sprinkler arcs if plants have grown and blocked the spray
- Check for dry patches or runoff
- Review controller schedules against actual weather conditions
- Inspect for leaks in visible pipework and valve boxes
Autumn winterisation (October–November)
Winterisation protects the system from frost damage:
- Shut off the water supply
- Drain the system using drain valves or compressed air
- Protect or remove the pump if it is not frost-proof
- Insulate above-ground components
- Programme the controller to off or standby
Signs a system needs servicing between visits
- Dry patches on the lawn or wilting plants in borders
- A sprinkler that does not pop up or stays up permanently
- Water pooling or running on paths and driveways
- Higher than expected water bills
- A controller showing an error or flow alarm
- A zone that does not come on at all
Key Takeaway
Service an irrigation system at least once a year — ideally a spring start-up and an autumn winterisation — and schedule a mid-season check for large or complex gardens to catch problems before they cause damage.
Frequently Asked Questions
Can I service my irrigation system myself?
Basic tasks like cleaning nozzles and adjusting the controller are straightforward, but pressure testing, pump checks and winterisation are best done by a professional to avoid damage.
What happens if I don't winterise my system?
Water left in pipes, valves and the pump can freeze and expand, cracking pipework and valve bodies. Repairs are typically far more expensive than the cost of winterisation.
How long does a service take?
A residential system takes 1–2 hours; a large estate or commercial system can take a full day depending on the number of zones.
Do smart controllers need servicing?
Yes. The controller itself may update its software automatically, but the valves, sprinklers, sensors and pipework still need physical inspection and maintenance.