Run one zone at a time and walk it from start to finish. That single habit catches most irrigation faults, because almost everything wrong with a system is visible while water is moving and invisible the rest of the time. Add a meter check with all zones off to catch leaks that show nothing at the surface, and you have covered the majority of what goes wrong.
Why walking the zones is the whole technique
Irrigation systems run before dawn, so nobody ever sees them work. That is the root cause of almost every expensive irrigation problem: a fault that would be obvious in daylight runs unwitnessed for weeks.
Starting each zone manually in the afternoon and walking it takes under an hour on most properties, and it finds broken heads, misalignment, lost coverage, misting, weak zones, wet ground that should not be wet, and heads that never pop up at all.
You do not need equipment for this, and you do not need to diagnose anything. Observing accurately is the valuable part — and if you do call someone, a homeowner who says "zone four is fine at the near end and the last two rotors barely turn" has already saved half the diagnostic time.
The walkthrough
- Start with everything off and watch the meter. With no zone running, the irrigation side should be still. Movement means a mainline leak or a valve seeping. Note it — this one is worth acting on quickly.
- Start zone one manually and walk it. Watch the heads rise. Any that do not rise, do not turn, or rise and stay stuck up are noted.
- Check each head’s spray. Broken caps, missing heads, a head geysering water, a torn wiper seal weeping around the stem, a nozzle blocked by debris.
- Check where the water is going. Spray hitting pavement, fences or the house is water you are paying for that waters nothing. Note which heads.
- Look for gaps between arcs. Heads should reach roughly to their neighbours. A visible dry gap between two arcs is a coverage problem, and no amount of extra run time will fill it.
- Look at the quality of the spray. A fine mist that drifts means pressure is too high for those heads. Weak, short, collapsing throw means pressure or flow is too low.
- Walk the ground, not just the heads. Soft, saturated or bubbling ground away from any head is a lateral leak on that zone.
- Repeat for every zone, and note the differences. One weak zone among healthy ones points somewhere quite different from every zone being weak.
- Open the valve boxes and look. A box standing full of water, or wet when nothing has run, is worth reporting. Look, do not disassemble.
- Review the controller. Programs, start times, run times, seasonal adjustment, and whether a rain sensor bypass has been left on. Check for duplicated or overlapping programs.
- Write down what each station waters. Inside the controller door. This is the most useful thing you can do for every future repair.
What the patterns mean
| What you saw | What it usually means |
|---|---|
| One zone dead, others fine | That zone’s valve, solenoid or station wire |
| Every zone weak | Supply pressure, a partly closed shutoff, or a mainline problem |
| One zone weak, others fine | A leak on that zone, a partly opened valve, or too many heads on it |
| Misting on every zone | Pressure too high — pressure regulation is the fix, not shorter run times |
| Meter moving with everything off | Mainline leak or a seeping valve — this runs constantly |
| Wet ground away from a head | Lateral leak on that zone |
| Dry gap between two working heads | Coverage problem — spacing, nozzle or pressure, not run time |
| Nothing runs at all, controller lit | Fuse, common wire, water supply or rain sensor |
| A zone will not shut off | Stuck valve or a failed controller output — act on this one, it never stops |
Want this looked at rather than read about?
Diagnostic-first visits across North Georgia. Call 770.335.8595 or request service — you get an estimate before any work begins.
Where to stop
Safe and useful: everything above. Running zones, walking the property, looking in valve boxes, watching the meter, reviewing the controller programming, clearing debris from around a head, gently cleaning a nozzle screen.
Worth leaving alone: anything inside an energised controller. The station-by-station voltage and resistance measurements that diagnose electrical faults are taken on live circuits, and their value lies in interpreting readings against each other rather than in any single number. Anything touching the household power supply to the controller is electrical work.
Also worth leaving alone: digging for a suspected leak. It is easy to dig in the wrong place, and easier to dig through a second line or a wire bundle on the way. Locating equipment exists for this reason.
And do not defeat a fuse. If a fuse blows, something in the field is shorted, and fitting a larger one converts a cheap repair into a damaged controller.
What to report when you call
Irrigation Medics bills $125 for the first hour on site and $80 per hour after, with parts separate and an estimate before work begins. Since the first hour is diagnosis plus repair time, the observations above translate directly into more repair happening inside it. See request service.
- Which zones are affected, and which are fine. This single distinction narrows the diagnosis more than anything else.
- Whether the controller runs a zone manually.
- Whether you can hear valves clicking at the manifold when a zone is called.
- Whether the meter moves with everything off.
- When it last worked, and what happened around then — a storm, a fence installation, landscaping, a hard freeze.
- Whether the water bill has changed.
- Roughly how many zones the system has and where the controller and valve boxes are.
- Photos of anything odd. They are genuinely useful.
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