Spring Irrigation Startup: How to Turn on a System Without Damage
A system that was properly winterized in the fall is not automatically ready to run in spring. Components shift. Heads get damaged over winter. Pressure surges during startup can crack pipe if the refill is rushed.
The process below applies to most residential and light commercial systems. In the South, startups typically begin in January or February. In the North, where the ground freezes, late February through April is more common depending on conditions.
Before You Start
Inspect the system visually before introducing any water. Walk the zones and look for heads that are cracked, tilted, or clearly damaged. A broken head under pressure can injure a nearby worker and create an immediate repair situation. Wear eye protection and gloves throughout the startup process.
The Startup Sequence
- Vent the system first. Open valves, couplers, and air vents. Turn sprinkler heads to the open position. Check the backflow preventer and valve box for visible damage or signs of freezing.
- Set pressure low before filling. Start below 50 PSI. This is the most important step for preventing water hammer and surge damage to pipes.
- Fill the system slowly. Assign crew members to different points throughout the system to monitor flow. Once air has cleared and water flows steadily from each point, close that drain and move on. Fill from the highest elevation point downward.
- Activate zones one at a time. Keep pressure below 50 PSI throughout this step. A drop in pressure at a monitoring point indicates a line break somewhere upstream of that location.
- Check every head through its full cycle. Look for heads that are not rotating, spraying off-pattern, or misaligned. Check filters for debris.
- Reprogram the controller. Reset run times and schedules based on current seasonal need. Do not simply restore the previous year's program without reviewing it.
Common Mistakes
Filling the system too fast is the most costly error. Pressure surges during a rapid fill can crack lateral lines, pop fittings and break heads. A slower fill with lower initial pressure costs a few extra minutes and prevents a far more expensive repair.
Leaving before completing a full run cycle is the second most common issue. Problems that are easy to fix during startup become callback situations if they are not caught on the first visit.
What to Check While the System Is Running
Spring startup is the most practical time to assess the overall condition of the system. With every zone running, it is easier to spot heads that have degraded, nozzles that are partially blocked, and coverage patterns that no longer match the landscape as it has grown.
If heads are showing significant age or the controller lacks weather-responsiveness or remote access, the system is running less efficiently than current equipment allows. High-efficiency nozzles, smart controllers and drip zones in planting beds are all components that can be added to an existing system without a full reinstall.
