What to Check After a Hard Freeze | Irrigation Freeze Damage

Yard Smarts guide

The damage usually shows up when you turn it back on

Our winterization guide covers what to do before a freeze. This is the other half: what to check afterwards, and in what order.

The important thing to understand is that freeze damage to an irrigation system is almost always invisible while the water is off. A cracked backflow assembly looks completely normal until it is pressurised — at which point it becomes a fountain, sometimes an expensive one, sometimes at three in the morning.

So the rule is simple: inspect before you pressurise, not after.

Backflow preventer and irrigation components

In this order

What to check, and when

1Wait until it is properly above freezing

Not the first sunny afternoon in the middle of a cold snap. Wait until night-time temperatures are reliably above freezing, because turning water back into a system and then refreezing it does more damage than the original event.

2Look at the backflow assembly first

This is the most common casualty by a wide margin — it is brass, it is above ground, and it holds water. Look for a split in the body, a cracked bonnet or test cock, a bulge, or a hairline you can catch with a fingernail. Brass splits along a seam when the water inside it expands.

3Check exposed pipe, valves and the meter box

Any above-ground pipe, the riser up to the backflow, and anything in a shallow or uninsulated valve box. Look for splits, and for fittings pushed apart.

4Turn the water on slowly, and stand there

Open the main irrigation valve slowly rather than all at once, and watch and listen. Do not walk away. If something is cracked, this is the moment you find out, and you want your hand on the valve when you do.

5Run each zone one at a time

Watch the whole zone run. You are looking for heads that do not rise, new wet patches, geysers where a head has split, and pressure that is noticeably down on what it was.

6Read the meter with everything off

Once you are done, turn everything off and read the water meter, then read it again two hours later. Movement means something is leaking underground that you cannot see.

What tends to break

The usual casualties

The backflow preventer

By far the most common, and the most expensive small part in the yard. Brass cracks when water inside it freezes and expands. Often it looks perfect until pressurised.

Exposed pipe and risers

Anything above ground or barely below it. PVC splits lengthwise, and the split can be fine enough to miss until there is pressure behind it.

Valves and valve boxes

Shallow boxes that filled with water and froze. Cracked bonnets and split solenoids show up as a zone that will not run or will not shut off.

Heads and nozzles

Water left standing in a head can crack the body. Usually cheap to fix, and usually only found by running each zone and watching.

Hose bibs and connected hoses

A hose left attached over a freeze keeps water sitting in the bib. That failure often shows up inside the wall rather than outside, which is why it is worth checking.

Backflow on a fire or irrigation line at a commercial site

Same failure, much bigger consequence. On managed properties we shut systems down ahead of a freeze remotely, which is one of the quieter benefits of remote water management.

Plants and turf

Do not start cutting yet

The instinct after a freeze is to tidy up the brown. Resist it for a few weeks.

Damaged growth is insulation. The dead top of a plant protects the crown and roots from the next freeze, and in North Texas there is almost always a next freeze.
You cannot tell what is dead yet. Plenty of things that look finished in January push new growth from the base in March. Cutting hard in February removes the plant’s reserves and can turn survivable damage into a dead shrub.
Wait for new growth, then prune to it. Once you can see where the plant is alive, cut back to that. Late spring is soon enough for almost everything.
Brown turf in winter is dormant, not dead. Warm-season grasses here go brown every winter by design. Judge the lawn in late spring after green-up, not in February.
Do not fertilise to “help it recover”. Pushing growth on a stressed plant out of season makes things worse, and feeding dormant turf feeds the weeds.

Next time

Most of this is preventable

Freeze damage is one of the few landscape problems that is almost entirely avoidable with an afternoon of preparation.

Winterization guide

Shutting down, draining and insulating — step by step, before the first hard freeze.

Read the guide →

Repairs

Cracked backflow, split lines and valves that will not close. We do this work year round.

Irrigation repair →

Already a customer?

Send a repair request through the residential portal and it gets logged and routed.

Submit a request →

Commercial & HOA

Managed properties get shut down remotely ahead of a freeze rather than by a truck roll.

Grounds maintenance →

Something cracked?

Freeze repairs are what we do in January. Tell us what you found.

Get an Estimate Call (972) 240-8082

FAQs

After-freeze questions

How soon can I turn the system back on?

Once night-time temperatures are reliably above freezing, not on the first mild afternoon of a cold snap. Refilling a system and then refreezing it causes more damage than the original freeze.

My backflow looks fine. Am I clear?

Not necessarily. Cracks in brass are often hairline and invisible until the assembly is pressurised, which is exactly why you should open the main valve slowly and stay next to it rather than turning it on and going indoors.

Should I cut back everything that went brown?

Not yet. Damaged growth protects the crown from the next freeze, and a lot of what looks dead in January comes back from the base in spring. Wait until you can see new growth, then prune back to it.

Is my lawn dead?

Almost certainly not. Warm-season grasses in North Texas go brown every winter as a matter of course. Judge the lawn after spring green-up, not during dormancy.

The system runs but one zone is weak now. Related?

Very possibly. A split lateral line loses pressure to the ground rather than to the heads, and it can be subtle. Run the zone and walk it looking for a soft or unusually green patch.

Can you check it for us?

Yes — it is a large share of what we do in January and February. If you would rather not open the valve yourself and find out the hard way, that is an entirely reasonable position to take.

Let’s talk

Get an estimate

Tell us what you found and whether the system has been turned back on yet.

Prefer to talk? Call (972) 240-8082, Monday to Friday, 8:00 AM to 5:00 PM.