When to Turn On Your Sprinkler System on the North Shore: A Complete Spring Startup Guide

Spring is finally here on the North Shore, and if you’re like most homeowners in Highland Park, Winnetka, or Glencoe, you’re wondering: when is it safe to turn my sprinkler system back on?

Turn it on too early and you risk frozen pipes, cracked fittings, and expensive repairs. Wait too long and your lawn misses the critical early-season watering window that sets it up for a green, healthy summer.

Here’s everything you need to know about spring sprinkler startup for homeowners in the North Shore, Lake County, and surrounding communities.

When Should North Shore Homeowners Start Their Sprinklers?

The short answer: mid-April to mid-May for most of the North Shore and Lake County. But the calendar date matters less than these two conditions:

• Nighttime temperatures have stayed above freezing consistently for at least 1–2 weeks
• Soil is frost-free at least 12 inches below the surface

Homeowners closer to the lake — Kenilworth, Wilmette, Winnetka, Glencoe, Highland Park — often benefit from the lake effect keeping temperatures slightly milder. But don’t let a warm week in March fool you. Communities further inland like Libertyville, Deerfield, and Northbrook can hold frost a bit longer in low-lying areas.

A good rule of thumb: wait about one week past your area’s last expected frost date. For the North Shore, that’s typically around April 20th, which puts your safe startup window around late April to early May.

Your 7-Step Spring Startup Checklist

Don’t just flip the switch and hope for the best. A proper startup protects your system and catches problems before they become expensive.

1. Inspect Your Backflow Preventer

Your backflow preventer protects your home’s drinking water from contamination. Before anything else, visually inspect it for cracks, leaks, or winter damage. Many North Shore municipalities — including Highland Park, Deerfield, and Northbrook — require an annual backflow test. Now is the time to schedule it.

2. Close All Drain Valves

If your system was properly winterized last fall, the drain valves should still be open. Close them all before pressurizing the system.

3. Turn the Main Valve On — Slowly

This is the most critical step. Open your main water valve about one-quarter turn and wait a few minutes. Then move to halfway. Listen for water flowing through the system. Once the flow stops, open it fully.

Why does this matter? Opening too fast creates water hammer — a pressure surge that can crack pipes, blow fittings, and launch sprinkler heads out of the ground. We see this every single spring across the North Shore.

4. Test Each Zone One at a Time

Run each zone manually from your controller for 2–3 minutes. Walk the yard while each zone runs and watch for:

• Heads that don’t pop up (likely clogged or damaged)
• Geysers or flooding (broken line or missing head)
• Low pressure in a zone (possible underground leak)
• Heads spraying sideways or not rotating (need adjustment or replacement)

This is especially important for properties in Winnetka, Kenilworth, and Glencoe where mature landscaping and large lots mean more zones and more opportunities for winter damage to go unnoticed.

5. Check and Adjust Sprinkler Heads

Winter frost heave pushes heads out of alignment every year. Look for heads that are tilted, sunken, or spraying onto driveways and sidewalks instead of your lawn. A simple adjustment now saves water all summer.

6. Reprogram Your Controller

Don’t jump straight to your summer watering schedule. In early spring, your lawn needs about 50–60% of the water it needs in July. Start with shorter run times and gradually increase as temperatures rise.

If you have a smart controller like a Rachio or Hunter Hydrawise, update the seasonal adjustment setting rather than changing individual zone times.

7. Inspect for Leaks Over the Next 48 Hours

After startup, keep an eye on your water meter and watch for any unexplained wet spots in the yard. Slow leaks from underground cracks often don’t show up immediately — and on larger North Shore properties, a leak can run for days before you notice it.

3 Common Spring Startup Mistakes We See Every Year

After 40 years of servicing sprinkler systems across the North Shore and Lake County, here are the mistakes we see homeowners make most often:

Starting too early. One warm week in March doesn’t mean winter is over. We’ve seen hard freezes in April crack systems that were turned on prematurely — even in lakefront communities like Wilmette and Highland Park.

Skipping the backflow test. Many North Shore and Lake County municipalities require annual backflow testing. Skip it and you could face fines — or worse, contaminated water.

Ignoring small problems. That one head that sprays a little crooked? That zone that runs a few minutes short? Small issues compound all summer into dead spots, wasted water, and higher bills. On large properties in Kenilworth and Glencoe, a single misaligned head can waste hundreds of gallons per season.

When to Call a Professional

A DIY startup is fine if your system is simple and you’re comfortable with the process. But call a pro if:

• Your system is more than 10 years old
• You notice significant pressure loss in any zone
• You see standing water or soggy spots that weren’t there before
• Your backflow preventer needs its annual test
• You have a larger property with 8+ zones

Ready for Spring? We’ll Handle It.

At American National Sprinkler & Lighting, we’ve been starting up sprinkler systems across the North Shore for over 40 years. Our spring startup service includes a full system inspection, head-by-head adjustment, controller programming, and backflow testing — so your lawn is ready for summer from day one.

We proudly serve Highland Park, Winnetka, Glencoe, Kenilworth, Wilmette, Northbrook, Deerfield, Libertyville, Lake Forest, and communities throughout the North Shore and Lake County.

📞 Call (847) 566-0099 or request a free estimate to schedule your spring startup today.