Every spring, homeowners across New England pack away the snow blowers, pull out the mowers, and dream of a lush, green lawn. But one critical step gets overlooked far too often: properly starting up the irrigation system after winter. Most homeowners do not think about their sprinklers until a heat wave hits in July and the lawn starts turning brown — and by then, you are already behind. The time to open your system is spring, well before you need it, so that when summer arrives and your landscape is counting on every drop, everything is inspected, calibrated, and ready to go. This is not just about turning a valve and calling it a day. Done right, spring startup protects your investment, conserves water, and sets the foundation for a healthy lawn and garden all season long. Done wrong — or put off until it is urgent — it can cost you hundreds in repairs and leave your landscape struggling from the start.

Here’s what every homeowner needs to know.

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Why Spring Startup Actually Matters

Your irrigation system endured months of freezing temperatures, soil movement, and dormancy. Even if you winterized properly last fall, the system needs a careful, methodical restart – not a rushed one.

Protect Your Investment

A professionally installed irrigation system can cost anywhere from $4,000 to $16,000 depending on the size of your property. The components – pipes, valves, backflow devices, and heads – are durable, but not indestructible. Pressurizing a system too quickly without inspecting for any freeze damage or shifted valves could result in further damage. It’s important to start up carefully, too quickly and the water rushing through your mainline can cause a “water hammer” effect, popping fittings or causing minor leaks only visible in your water bill. A 30 minute startup process can prevent a $500 repair call.

Catch Winter Damage Early

No matter how well you winterized, winter is unpredictable. Frost can heave pipes. Shifting soil can knock heads out of alignment. Rodents have been known to chew through wiring. The startup process is your first opportunity to inspect the entire system and identify any issues before the season is in full swing — when repairs are far more disruptive.

Set Your System Up for Efficiency

An irrigation system that isn’t properly calibrated wastes an enormous amount of water. The EPA estimates that a typical U.S. household uses about 30% of its water outdoors, and as much as 50% of that is wasted due to overwatering, evaporation, and runoff. Startup is the ideal time to audit your zones, adjust spray patterns, and update your controller schedule to match current weather and seasonal plant needs.

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Spring Startup: A Step-by-Step Guide

1. Check the Backflow Preventer First

Before you touch anything else, locate your backflow preventer — the device that keeps irrigation water from contaminating your home’s drinking water supply. Inspect it for cracks or damage from freezing. The test cocks (small valves on the device) should be in the closed position from winterization. If you see any visible cracking or if the unit feels loose, call a licensed plumber or irrigation professional before proceeding. Many municipalities require annual backflow testing by a certified technician — check your local codes.

2. Restore Water to the System Slowly

This is the single most important technique for preventing damage at startup: open the main shutoff valve slowly. Do not crank it fully open in one motion.

Turn the valve a quarter-turn, wait 30 seconds, turn another quarter-turn, and repeat until fully open. This gradual pressurization prevents “water hammer” — the damaging pressure surge that occurs when water rushes suddenly into a depressurized system. Water hammer can crack pipe fittings, damage valve diaphragms, and stress the backflow preventer.

As the system pressurizes, walk the property and listen for any hissing, spurting, or obvious leaks.

3. Inspect Each Zone Manually

Activate each zone one at a time using your controller or the manual bleed screws on each valve. As each zone runs, walk it entirely and check for:

• Broken or tilted heads — Heads should sit flush with the ground and pop up cleanly. A head that sprays sideways or stays partially submerged is wasting water.
• Clogged nozzles — Restricted spray patterns often indicate debris in the nozzle. Most nozzles unscrew easily for cleaning.
• Dry spots or pooling — These indicate coverage gaps or heads spraying in the wrong direction.
• Zone runtime — Note whether any zone seems to be running unusually long before the area is adequately covered.

4. Adjust Head Alignment and Spray Patterns

Rotor heads and spray heads are adjustable for a reason — your lawn’s needs change, and so does the landscape. Spring is the time to fine-tune:

• Arc and radius adjustments on rotor heads to avoid watering driveways, sidewalks, or structures
• Fixed-spray nozzle swaps if coverage patterns no longer match the planting area
• Head height — Raise or lower heads as needed to clear new growth or hardscaping changes

Use a flat-head screwdriver to adjust most rotor heads. Consult your head manufacturer’s instructions for model-specific adjustments. Many heads have specialized tools come with them.

5. Update Your Controller Programming

Your fall schedule is not your spring schedule — and it’s definitely not your midsummer schedule. Irrigation needs vary significantly with temperature, rainfall, and plant growth stage. At startup, program conservatively:

• Early spring: Plants are emerging from dormancy and soils are often still moist from snowmelt. Start with shorter run times and fewer days per week.
• Adjust as needed: Revisit your schedule every 3–4 weeks or after significant weather changes.
• Use a rain sensor or smart controller: If you don’t already have one, consider upgrading. A smart controller that connects to local weather data can reduce water usage by 20–50% and pay for itself within a season or two.

A good rule of thumb for cool-season turf in spring: 1 inch of water per week, including rainfall. Use a simple rain gauge to track natural precipitation and adjust runtime accordingly.

6. Check the Controller and Wiring

While you’re at the controller, verify that:

• The current date and time are correct (power outages over winter often reset controllers)
• All zone programs are intact and accurate
• Any seasonal adjustments from last fall have been cleared
• The rain sensor (if present) is functioning — manually activate it to confirm it interrupts watering

If a zone fails to activate at the controller but runs fine when you manually bleed the valve, you likely have a wiring or solenoid issue. A multimeter can help diagnose solenoid problems; a qualified irrigation technician can trace field wiring faults.

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Common Startup Mistakes to Avoid

Opening the water supply too fast. As covered above, always pressurize slowly. This one habit prevents the majority of startup-related pipe and fitting damage.

Skipping the backflow preventer inspection. It’s not glamorous, but it’s legally and practically critical. A failed backflow preventer can contaminate your home’s water supply.

Running all zones at maximum time from day one. Overwatering in early spring encourages shallow root growth and can promote fungal disease. Start conservatively and increase as temperatures rise.

Ignoring misaligned heads. A rotor spraying onto a concrete driveway wastes thousands of gallons over a season. Spend the extra five minutes making the adjustment.

Using last year’s schedule without reviewing it. Landscapes change. New plantings, removed trees, expanded beds — all of these affect how water needs to be distributed. Treat each startup as a fresh audit.

Not testing every zone. It’s tempting to activate a couple zones, see water coming out, and declare success. But a cracked lateral line in Zone 5 won’t announce itself until it’s flooded your garden bed for a week. Walk every zone, every year.

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When to Call a Professional

Most homeowners can handle a basic startup with confidence. But there are situations where it pays to bring in a licensed irrigation professional:

• Your backflow preventer shows visible damage or your municipality requires certified testing
• A zone fails to activate and you can’t identify the cause
• You suspect a main line break (dramatic drop in pressure across all zones, soggy areas of turf with no obvious cause)
• You want a full system audit and efficiency upgrade

Many irrigation companies offer spring startup service packages that include a full inspection, adjustment, and controller programming for a flat fee. For larger or more complex systems, this is often money well spent.

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The Bottom Line

Your irrigation system is a significant piece of infrastructure — one that quietly does its job every day without much recognition. Giving it a proper, methodical startup each spring is how you keep it running efficiently, extend its lifespan, and protect the landscape it serves.

Take the time. Walk the zones. Adjust the heads. Update the schedule. Your lawn will show its appreciation all season long.

Calvin