Seasonal Advice
Spring Sprinkler Startup, Done Right
Slamming the valve open in April is how spring repairs get expensive. The right startup is slow, methodical, and catches winter's damage while it's still cheap.
- Published
- August 15, 2026
- Reading
- 6 min
- By
- BigBoy Builders
When to Start Up
Late April into May on the Front Range — after hard overnight freezes are done. An early warm week in March fools a lot of homeowners into pressurizing, and then a mid-April cold snap refreezes a now-full backflow preventer. Cool-season lawns barely need irrigation before May anyway; there's no prize for being first on the block.
The Slow-Fill Rule
The single most damaging thing you can do to an irrigation system is open the main shutoff fast. Water slams into empty lines at full pressure, and that water hammer cracks fittings and valve diaphragms that survived the whole winter.
Backflow test cocks and drain valves get closed first — they were left open at the blowout on purpose.
Let the system fill slowly — listen to it. Filling a typical residential system gently takes a few minutes, not a few seconds. Only then open the valve fully.
Cycle zones one at a time from the controller and walk the yard while each runs. You're looking for winter's casualties — see the checklist below.
Last year's summer schedule is still in the controller. Spring lawns want a fraction of that — start low, add water as heat arrives.
What to Look For on the Walk
- A zone with weak pressure across all heads — classic sign of a cracked buried line or leaking valve
- Water bubbling up or a soggy spot that stays wet between cycles — a break at that low point
- Heads that don't pop up, don't rotate, or spray a broken fan — winter debris or cracked internals
- Geysers where a head used to be — snowplow, shovel, or aerator casualties
- Spray misting heavily or overshooting beds — pressure too high or nozzle mismatch, both fixable and both wasteful
- The backflow preventer dripping or hissing once pressurized — it froze at some point; budget for a rebuild
Questions / Field Notes
Frequently asked questions
Want the startup handled?
BigBoy runs the slow fill, walks every zone, fixes winter casualties on the spot, and sets the controller for the season.
When it's past DIY
The services this connects to.
In practice
Where we've done it.
Before After 
Backflow Valve Installation
Backflow valves are generally required by local plumbing codes to prevent water contamination. This project involved installing a backflow valve in a residential property to ensure compliance with local regulations and protect the water supply.
- Services
- Sprinkler & Irrigation Systems
- Tags
- Irrigation, Plumbing
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