Spring Irrigation Startup: 5 Steps to Protect Your Pacific Northwest Landscape

After months of Pacific Northwest rain, the transition to drier spring weather is when your irrigation system earns its keep. But flipping the switch without proper preparation can mean cracked pipes, flooded zones, and wasted water. Here’s our field-tested five-step startup process, refined over 37 years on Whidbey Island.

1. Inspect Before You Pressurize

Walk every zone before turning on the water. Look for exposed risers that may have been damaged by frost heave, displaced heads from winter landscaping or foot traffic, and any visible cracks in above-ground piping. On Whidbey Island, our freeze-thaw cycles between December and February are the primary culprit for hairline fractures in PVC laterals.

2. Open the Main Valve Slowly

This is where most homeowners make their biggest mistake. Slamming the main valve open sends a pressure surge through empty pipes — a phenomenon called water hammer — that can split fittings and blow out diaphragms in your valve manifold. Instead, open the main valve one-quarter turn and let the system fill gradually over 3–5 minutes. Listen for hissing or gurgling that indicates air pockets clearing.

3. Test Each Zone Individually

Run each zone for 2–3 minutes while walking the coverage area. Check for heads that aren’t popping up fully (often caused by debris in the spring housing), misaligned spray patterns, and low-pressure zones that could indicate a line leak underground. Mark any issues with landscape flags so your technician — or you — can address them systematically.

4. Adjust Heads for Spring Growth

Your landscape has changed since last fall. Perennials are coming back, shrubs have put on new growth, and that ornamental grass you planted is twice the size it was in October. Adjust rotor arcs and spray head patterns to account for new growth that may be blocking coverage. This is also the time to convert any fixed-spray heads in planting beds to drip irrigation — a change that typically reduces water use by 30–50% in those zones.

5. Program Your Controller for the Season

Pacific Northwest springs are unpredictable. We recommend starting with run times at 50% of your peak summer schedule and increasing gradually as temperatures rise and rainfall decreases. If your controller supports a rain sensor or soil moisture sensor, now is the time to verify those sensors are functioning. A working rain sensor alone can save 25–35% on your annual water bill.

When to Call a Professional

If you notice persistent low pressure across multiple zones, soggy areas in your yard when the system is off, or a water bill that spikes unexpectedly, you may have a mainline leak or a failed backflow preventer. These are repairs best left to a certified irrigation technician who can pressure-test the system and pinpoint the issue without unnecessary excavation.

At Whidbey Island Landscaping, we offer comprehensive spring startup service that covers all five steps plus a full system audit. Contact us to schedule your appointment before the dry season arrives.