How to Winterize Your Irrigation System in North Texas Before the First Freeze

North Texas winters are deceptive. Most years, DFW skips through fall without a serious freeze until late November or December — which tempts homeowners into complacency about winterizing their irrigation systems. Then a blue norther drops the temperature from 65°F to 19°F overnight, and the cracked pipes and blown backflow preventers start appearing all over the neighborhood. Irrigation repair bills after a hard freeze can easily run $300 to $1,500 depending on how many components fail. Proper winterization takes an hour or two of preparation and costs a fraction of that. Here’s exactly what to do and when to do it for North Texas conditions.

Why North Texas Irrigation Winterization Is Different From Northern States

In colder climates, irrigation winterization is standard protocol because the ground freezes deep and every pipe needs to be blown out with compressed air. North Texas is a different situation. Our freeze events are typically brief — 12 to 72 hours of subfreezing temperatures followed by a return to normal weather. The ground rarely freezes more than a few inches deep. But that’s exactly what makes our freeze events so damaging to irrigation systems: the pipes and components are installed assuming mild winters, and a sudden hard freeze finds water sitting in those components with no insulation buffer.

The target components in North Texas are not the in-ground supply lines (which are deep enough to be safe in most years) but the above-grade and near-surface components: backflow preventers, valve boxes, controller clocks, and any pipe sections that run above grade or shallow near-surface.

What to Winterize and What to Skip

Understanding the risk level of each component saves time and targets your effort correctly:

• Backflow preventer — HIGH priority: This is the most commonly damaged component in North Texas freeze events. It sits above grade, often in an exposed location, and contains water in its body at all times when the system is active. The double-check or pressure vacuum breaker valves crack frequently in hard freezes if unprotected.
• Valve boxes and manifolds — MEDIUM priority: These sit just below grade, sometimes with minimal cover. During extended freezes (more than 24 hours of subfreezing temps), water in the valve solenoids and manifold bodies can freeze and crack.
• Controller (timer) — LOW to MEDIUM priority: Modern controllers are generally frost-proof but exposed wire connections and display screens can be damaged by moisture and freezing if the controller is mounted in an exposed location. Mostly this is about protecting the device, not preventing pipe damage.
• In-ground supply lines — LOW priority: At 10 to 14 inches of depth (standard DFW installation depth), supply lines rarely freeze even in hard freeze events unless the freeze lasts more than 3 to 4 days, which almost never happens here.
• Sprinkler heads — LOWEST priority: Standard pop-up heads drain automatically when pressure is released. They generally survive North Texas freezes without special attention.

When to Winterize in North Texas

The target window in DFW is mid-November to early December. Check the long-range forecast — you want to complete winterization before the first predicted overnight freeze, but there’s no need to shut everything down in October while temperatures are still in the 70s. A typical DFW fall allows you to continue watering through mid-November with the system fully active. Once nighttime lows are regularly dropping below 40°F and freezing temperatures are on the 10-day forecast, it’s time to winterize. With climate variability, some years that’s Thanksgiving week; some years it’s after Christmas. Let the forecast guide you rather than the calendar.

Step-by-Step Winterization Process for North Texas

Step 1 — Turn Off the Irrigation Water Supply

Locate your irrigation system’s main shutoff valve — typically near the backflow preventer, near your water meter, or inside the garage. Turn it off completely. This stops new water from entering the system but leaves water sitting in the pipes and components downstream.

Step 2 — Drain the Backflow Preventer

This is the most important step in North Texas winterization. Your backflow preventer has test cocks (small valves) that allow you to drain the device body. Turn both test cocks to a 45-degree angle (diagonal position) — this puts them into a partially open bleed position that lets water drain out of the body. Do not leave them fully open, which would create a drainage path for any system water that refills during a mid-winter warm spell. The 45-degree position is the winterizing position for North Texas double-check valves.

Step 3 — Insulate the Backflow Preventer

Even after draining, wrap the backflow preventer with foam pipe insulation, commercial irrigation wrap, or a purpose-made backflow preventer cover bag. Any hardware store in Arlington stocks these during fall. A simple wrapping significantly reduces the freeze risk on the brief but intense overnight freezes DFW experiences. Do not use cloth or non-waterproof materials — they absorb moisture and actually worsen freeze damage by holding wet material against the pipe.

Step 4 — Set the Controller to “Off” or “Rain” Mode

Do not unplug the controller — most controllers have a battery backup for programming but lose the clock settings when unplugged. Instead, switch to “Off” or use the “Rain” or “Seasonal Adjust” mode that suspends watering without clearing the schedule. This prevents the system from running during freeze events while maintaining all your zone programming.

Step 5 — Check Valve Box Covers

Walk your zone valve boxes and confirm lids are seated fully and aren’t cracked or missing. A tight lid provides minimal but meaningful insulation for the shallow valve manifolds. Replace cracked or missing covers — they’re inexpensive at irrigation supply stores and the difference in a hard freeze can matter.

Emergency Response When a Freeze Is Forecast and You Haven’t Winterized

If a sudden hard freeze is 24 to 48 hours out and you haven’t winterized, prioritize the backflow preventer. Drain and wrap it immediately. For the rest of the system — let it be. Do not attempt to run every zone to “clear” the pipes; that actually leaves water sitting in the heads and surface components at freeze time. The ground-level and below-grade components will almost always survive a typical DFW freeze without the full blowout that northern climates require.

Spring Startup After Winter

When temperatures stabilize above freezing in February or March, reverse the winterization process: restore water supply slowly, remove insulation wrap from the backflow preventer, return test cocks to their normal operating position, and walk all zones at low pressure to check for any damage before resuming full-season watering. A complete spring lawn care startup is also the right time to calibrate your irrigation output and set your schedule for the new season. For context on how grass type affects spring startup irrigation needs, see our comparison of shade-tolerant Bermuda varieties for DFW yards, which covers watering management differences between varieties.

Hamann’s Seasonal Reminder

We’ve been helping Arlington homeowners care for their lawns through Texas winters since 2006. Every hard freeze season, we see avoidable irrigation damage across the neighborhood — usually from homeowners who meant to winterize but forgot until the news was already showing temperature maps in the 20s. Put a November calendar reminder on your phone now. The backflow preventer wrap and test cock adjustment takes less than 20 minutes and can save you hundreds of dollars. And if the lawn needs fall or winter treatment alongside your winterization — pre-emergent timing, fall fertilization, fungus prevention — give us a call and we’ll handle the whole program.