When several heads on the same zone stop working, the cause is usually one thing they share rather than several individual failures. A break in the lateral line feeding them, a pressure problem on that zone, or debris distributed through the line after a repair will all take out a group of heads at once. Heads failing individually is possible but far less likely than a single shared cause.
Which heads failed tells you what failed
The second row is the most diagnostically useful pattern on this list. If heads one through four work and five through nine are dead, the break is between four and five, and that narrows the excavation to a known stretch of pipe.
| Pattern | Likely cause |
|---|---|
| Every head on one zone dead | Valve not opening, or a major lateral break bleeding off all pressure |
| All heads past a certain point dead | Lateral line break at that point — nothing downstream is getting pressure |
| Heads at the high end of a slope weak or dead | Pressure loss to elevation, not a fault |
| Scattered heads across the zone weak | Zone pressure low overall, or too many heads for the available flow |
| Several heads spraying but not rotating | Debris in the rotors, or pressure below what they need to turn |
| Several heads misting rather than spraying | Pressure too high, or worn nozzles |
| Several heads not popping up | Buried under mulch or sod, or wiper seals stuck |
The shared causes, in order of likelihood
- A lateral line break. Water escaping from a break upstream means the heads beyond it never see working pressure. The tell is poor performance across a group plus unusually high flow on that zone, often with water surfacing somewhere while the zone runs.
- A broken or missing head on the same zone. An open pipe takes a disproportionate share of the zone’s flow, so every other head drops below design pressure. One snapped head makes eight healthy ones look broken.
- Debris in the lateral. Soil and pipe shavings introduced during a repair distribute along the line and lodge in nozzles and screens. Typically several heads at once, and typically shortly after work was done.
- A valve not opening fully. A flow control stem closed down or a diaphragm not lifting completely restricts the whole zone. Everything runs, weakly.
- Zone pressure or flow inadequate for the head count. Often the result of heads added over the years for a patio or a new bed without adding capacity. Nothing is broken; the zone is over-subscribed.
- Buried heads. New mulch, new sod or raised grade means heads cannot reach spray height. Common after landscaping and entirely mechanical.
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.
What to check yourself
- Run the zone and walk it, noting exactly which heads work, which are weak and which are dead, and in what order along the line. Take a photo or sketch it.
- Look for water surfacing anywhere while that zone alone is running, including well away from the heads.
- Check whether dead heads are simply buried — clear mulch and soil from around a couple and run the zone again.
- Unscrew a nozzle or two from a weak head and look at the screen beneath. Visible grit points at debris in the line.
- Compare against a neighbouring zone. If every zone is weak, the problem is supply or pressure system-wide rather than this zone.
- Recall any recent digging or any repair made on that zone in the past few months.
Why replacing the heads is often the wrong first move
It is tempting, because the heads are what you can see. But if a lateral break is starving the zone, nine new heads will perform exactly as badly as the old ones did, and the money is wasted. If a single snapped head is dragging zone pressure down, replacing that one restores the other eight without touching them.
The right order is: establish whether the zone has working pressure at all, find and fix any break or open head, clear debris from nozzles and screens, then assess the individual heads that are still underperforming. By that point the list of genuinely failed heads is usually much shorter than it looked.
And because labour is billed by time, replacing the heads that do need it all in the same visit costs far less per head than dealing with them one at a time. Irrigation Medics bills $125 for the first hour on site and $80 per hour after, with parts separate.
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Services that fix this
Sprinkler Head Repair
Geysering heads, heads that will not pop up, spray on the driveway and the dry patches they cause.
Read more →Sprinkler Zone Repair
One zone dead while the rest run fine — the most common irrigation call there is, and the most diagnosable.
Read more →Low Sprinkler Pressure
Heads that barely rise, spray falling short, one zone weaker than the rest — and what actually causes it.
Read more →Where we work
Irrigation Medics repairs irrigation systems across Hall County and the Lake Lanier communities, the Gwinnett corridor through Duluth, Suwanee and Buford, and North Fulton and Forsyth — Johns Creek, Alpharetta, Milton, Roswell and Cumming. Same rates throughout. See the service area.