Houston Why the Order Matters More Than the Checklist
Every winter that brings a hard freeze to the Houston area — February 2021, December 2022, January 2024, January 2025 — leaves behind a quiet backlog of damage that doesn't show up until someone turns the water back on. The mistake most homeowners make at spring startup isn't forgetting a step. It's doing the right steps in the wrong order. A mainline that's sat empty all winter refills through dry pipe at surprising velocity, and if the isolation valve gets snapped open fast, that pressure surge can crack fittings that survived the freeze itself untouched. The fix isn't a different valve. It's patience.
The Actual Sequence
A proper spring startup after a freeze cluster follows a specific order, and skipping ahead is how a $150 repair turns into a multi-point failure:
- Open the isolation valve slowly. A quarter-turn at a time, pausing to let air and pressure equalize, not a single crank to full open.
- Walk the backflow preventer before anything else runs. This assembly sits above ground and above the highest sprinkler head by design — which also makes it the one component a freeze can actually reach. A hairline crack in the casting, often through the domed top of the assembly, will weep or spray the moment pressure arrives. Catch it here, dry ground, good light, before a single zone has run.
- Run every zone individually and watch it, not from the porch. Two kinds of failure only show up under pressure: a crack that was invisible when the pipe was dry, and an internal seal that ice damaged while the outer housing stayed intact and gave no visual clue anything was wrong.
- Check zone-to-zone behavior — a head that barely dribbles, a valve that won't fully shut, a controller station that doesn't fire — and note each one rather than fixing on the fly.
That sequence is really the heart of a spring pass over the whole system, and it's worth doing even in a year that felt mild, because the backflow assembly doesn't need a catastrophic freeze to crack — it needs one night at the wrong temperature with water sitting in it.
Why March Beats May
A cracked backflow preventer found in March is routine, scheduled work at an ordinary rate. The same crack discovered in late May — usually because someone finally noticed the yard wasn't getting watered, or water was pooling near the meter — is now competing with every other repair in the metro that got discovered the same way, at the same time, by homeowners who also put off the walk-through. Supply and scheduling tighten every year as the season moves on. The part doesn't get more expensive because it's May; the backlog does. If you only do one piece of preventive maintenance on an irrigation system all year, do it in March, not when the lawn starts showing it.
What Else to Check While You're Out There
The freeze inspection is a good excuse to catch other seasonal issues at the same time, especially anything related to Houston's clay. As the ground shifts through its wet and dry cycles — and it does so unevenly across a single yard, with the soil under a bed edge moving on a different schedule than the soil under a driveway apron — rigid pipe fittings and heads that were set flush last year can end up standing proud of grade or leaning off vertical by spring. A head that watered the lawn in October can be watering the curb by June if nobody looked. While you're walking the system:
- Note any head that's tilted or sitting higher than the turf around it.
- Listen for a bang when a zone shuts off, which usually points to a water hammer issue rather than anything frost-related.
- Check that a zone that won't come on at all isn't simply a wiring problem — a valve that opens by hand at the solenoid but not from the controller is an electrical fault, not a plumbing one, and that's worth knowing before anyone gets called out for a zone that won't turn on.
- Confirm the rain sensor wasn't knocked loose or left disconnected over winter.
None of this requires tools or special access — it's a slow walk around the yard with the controller running each zone one at a time, watching rather than listening from inside.
If the Backflow Assembly Failed
If the walk-through turns up a crack, a weep at a fitting, or an assembly that won't hold pressure, that's not a sign the whole system is in trouble — it's a sign the one above-ground, freeze-exposed component did exactly what it was always going to do eventually. Whether it needs a rebuild or a full replacement depends on where the damage is and how old the assembly is, and that's a judgment call worth getting from someone who can see it firsthand through a service like backflow preventer repair.
The single sentence version: pressurize slowly, check the backflow assembly before any zone runs, watch every zone individually, and get a cracked assembly scheduled in March rather than discovered in May.