Why should exposed backflow equipment be protected during a Houston freeze?
Short answer: Water trapped in vulnerable above-ground components can freeze, expand, and damage the assembly. The backflow preventer sits above ground — which makes it the most exposed, most freeze-prone part of the whole irrigation system.
Buried pipe is protected by the soil. The backflow preventer is not. It is a brass assembly full of water, sitting out in the open, and when the temperature holds below freezing for several hours, the water inside it expands as it turns to ice. That expansion cracks the body, splits fittings, and breaks internal check valves — damage that often does not show up until the water is turned back on in spring and the assembly starts leaking.
Protecting it takes a few steps, and they need to happen before the freeze, not during it. Texas A&M’s irrigation guidance for light to mild freezes — the kind Houston gets — is straightforward: turn off the irrigation controller, shut off the irrigation water supply at the isolation valve, insulate any PVC pipe exposed above ground, and drain water from above-ground components such as the backflow assembly. Draining means opening the test cocks slowly, letting the water run out, and leaving the ball valves at a 45-degree angle so any trapped water can escape. Then fit an outdoor-rated insulated cover over the assembly.
Two things people get wrong: blowing compressed air through the backflow preventer, and covering it so tightly that the air vents and drain outlets are blocked. Never blow air through a pressure vacuum breaker or reduced pressure assembly — drain it instead. And the insulated cover should protect the assembly without blocking its vents and drains.
What we check in Kingwood
This is a common question in Kingwood, and it is the kind of thing we test in the yard instead of guessing at from the driveway. We run the system, watch how the water is actually moving, and check the parts that cause this — before anything gets replaced. That is the same approach in the full Backflow Testing service page.
Related reading: Backflow Testing in Kingwood · All questions · Contact us
Learn more: TCEQ — Landscape Irrigator licensing (LI, IT, II) · 30 TAC Chapter 344, Landscape Irrigation — full rule text (§344.51: chemical injection requires an RPZ or air gap)
Frequently asked questions
When should I protect my backflow preventer?
Before the first hard freeze of the season — in the Houston area, a good rule is to have the system shut down and the assembly drained and covered by early to mid-November, and then watch the forecast for any early cold snaps.
Can I just wrap the backflow preventer in a towel?
A towel is better than nothing for a brief cold night, but a proper insulated backflow cover is the reliable option — it fits the assembly, stays in place in wind, and keeps the vents and drain outlets clear. The drain-and-insulate steps matter more than the cover alone.
Do you serve Kingwood?
Yes. Orion’s Rain serves Kingwood and the Lake Houston area — Kingwood, Atascocita, Porter, Humble, New Caney, Summerwood, Fall Creek, Huffman, and Eagle Springs. Call or text (281) 504-9998, 24 hours a day.
Related questions
- What does an irrigation backflow preventer do?
- Why should I inspect my sprinkler system after a Houston freeze?
- Why should an irrigation system have its own shutoff valve?
Get it looked at
If this sounds like your yard in Kingwood, call or text Orion’s Rain at (281) 504-9998 — 24 hours a day. We will test the system and tell you what is actually wrong, and what it will take to fix it the right way.
Orion’s Rain Smartscapes and Exteriors — (281) 504-9998 — LI0029444
Sources: Texas A&M School of Irrigation winterization guidance, via Casas Irrigation, “Sprinkler Winterization vs Blowout: Frisco 2026 Guide” and LawnGuru, “How to Winterize a Sprinkler System (Step by Step)” (four steps for light to mild freezes; never blow air through a PVB or RP assembly; do not block air vents and drain outlets).