Why won't my sprinkler heads pop up?
Updated August 2026
Sprinkler heads that rise slowly or stay flush with the grass usually come down to low pressure on the zone or a clogged nozzle screen: either not enough water reaches the heads to push them up, or grit has choked the tiny filter under the nozzle. If one head lags while the rest pop, clean that head first. If the whole zone is weak, the problem is pressure, either too many heads or a leak, and the list below sorts it out.
Safety first: an uncapped riser or a head with the nozzle removed can fire a jet of gritty water hard enough to sting an eye, so stand to the side, not over the head, when you pressurize a zone to test it. In freezing climates, water left in the lines is what cracks heads and pipes over winter, so blowing the system out before the first hard freeze prevents far more damage than any single spring repair.
Causes, most likely first
| Cause | How likely | The fix | Typical cost |
|---|---|---|---|
| Low zone pressure or too many heads | Most common | Reduce the heads per zone or find the supply restriction; healthy pop-up needs roughly 30 psi at the head. | Free to $150 |
| Clogged nozzle screen or filter | Common | Unscrew the nozzle, rinse the small filter screen under running water, and reinstall it. | Free |
| Riser jammed with soil or grass | Common | Clear the debris around the riser and flush the head with the zone running. | $0–10 |
| Cracked lateral line bleeding pressure | Occasional | Find the soggy spot, dig down, and splice in a fresh section of pipe. | $50–150 |
| Failing zone valve or diaphragm | Occasional | Rebuild the valve with a new diaphragm or replace the valve body. | $15–100 |
| Fouled backflow or inline filter | Rare | Shut the water, pull the screen, and clean out the accumulated grit and scale. | $0–25 |
Check these first
- Run the zone and watch which heads rise and which stay down. One dead head points to a clog; a whole weak zone points to pressure.
- Unscrew the nozzle from a lazy head and rinse the little filter screen under the riser; grit there is the top cause.
- Walk the zone for a wet, spongy patch or a geyser, which means a cracked lateral line is bleeding off the pressure.
- Count the heads on the zone. More rotors than the supply gallons-per-minute can feed leaves every one of them weak.
- Check the inline or backflow filter screen and the flow-control setting on the zone valve.
Prevent it next time
Most pop-up trouble is grit and pressure, both of which a spring startup routine catches early. Rinse the nozzle screens and run every zone at the season's first watering, the core of a yearly sprinkler test and the maintenance checklist. The bigger money-saver is a proper fall blow-out: skip it and freeze-cracked heads and lines are exactly the winterization bill you pay in spring.
When to call a pro
Bring in an irrigation tech when the whole zone stays weak after you have cleaned the nozzles and confirmed no head is jammed, because that usually means a broken lateral line or a failing valve underground. Locating and repairing a cracked line runs $100–250, and a valve rebuild or replacement $75–200. If several zones lost pressure at once, the problem is upstream at the backflow preventer or the main, which is a pro job.
Most of the causes above are maintenance problems wearing a disguise. OnOtto keeps the boring prevention on schedule so the 2 a.m. version doesn't happen.
Stop chasing symptoms, free for 30 daysFrequently asked questions
Why do some heads pop up and others do not on the same zone?
When most heads rise and one or two stay down, the low heads almost always have a clogged nozzle screen or a riser packed with soil, not a system-wide problem. Pull the nozzle off a lazy head, rinse the little filter screen, and flush the riser with the zone running. If instead every head on the zone barely lifts, the issue is pressure: too many heads for the supply, a partly closed valve, or a cracked line bleeding water off before it reaches the heads.
How many sprinkler heads can one zone run?
It depends on gallons per minute, not a fixed count. A typical residential zone delivers about 8–12 gpm, and each rotor head uses roughly 1.5–3 gpm while spray heads use less, so a zone commonly runs 4–6 rotors or a dozen-plus spray heads. Load more than the supply can feed and every head rises weakly and throws short. If a previous owner added heads to an existing zone, splitting it into two zones is often the real fix for chronic low pop-up.
Is low pressure a broken pipe or something cheaper?
Check the cheap causes first. Clogged nozzle screens, a partly closed valve flow-control, or a fouled backflow filter drop pressure and cost nothing to clear. A broken pipe announces itself: a soggy patch, a bubbling spot, or one head geysering while the rest go weak, because the crack dumps water before it reaches the heads. If cleaning the screens and opening the valve do not restore lift and you cannot find a wet spot, a pressure test tells you whether the supply itself is undersized.
How often should I clean the nozzle screens?
At least once a year at spring startup, and again any time a head starts throwing short or misting oddly. Grit, pipe scale, and bits of Teflon tape collect on the small screens under each nozzle and choke the flow. Cleaning them takes a few minutes per head and is a core step in a sprinkler maintenance checklist. Systems on well water or with older galvanized supply lines clog faster and are worth a mid-summer check too.