Spring Sprinkler Startup Checklist for Ontario Lawns
Bringing an irrigation system out of winter the wrong way cracks pipes and fittings. Follow this order of operations for a safe spring startup.
Timing matters more than the calendar
In the GTA, safe startup begins once overnight lows stay above freezing consistently, usually mid-April to early May. Charging a system during a late frost is the fastest way to split a lateral line.
The correct order of operations
- Inspect above ground first. Walk the property and look for heads pushed up by frost heave, damaged valve box lids and any landscaping changes.
- Open the main slowly. A quarter turn at a time. Filling the mainline fast creates a water hammer spike that blows fittings and the backflow device.
- Charge one zone at a time. Let each zone fill, then run it for two to three minutes.
- Check every head. Look for geysers, misting, and heads that never pop up.
- Verify the backflow preventer. No weeping, no continuous discharge.
- Reprogram the controller. Clear last year's schedule, set the clock, and start with short cycles while spring rain is still frequent.
- Test the rain sensor. Press the disc and confirm the controller pauses.
Spring programming for Southern Ontario
Cool-season grasses need roughly 25 mm of water per week including rainfall. In May, most lawns need one or two cycles per week, not daily watering. Frequent shallow watering breeds shallow roots and makes July worse.
When to book a professional startup
If your system has a backflow device requiring annual testing, more than six zones, or you had unresolved problems last season, book a startup service. Our technicians pressurize safely, audit coverage zone by zone, and hand back a written report of anything needing repair.