Sprinklers Not Popping Up? Low Pressure Causes & Fixes

A pop-up sprinkler is a simple thing. When the zone turns on, water pressure pushes the riser up out of its body. When the zone turns off, a spring pulls it back down, level with the lawn. So when pop-ups misbehave, it nearly always comes down to one of two questions: is something stopping this head from moving, or is too little water reaching it?

Rather leave it to us? Call us on (08) 6263 4644. Repairs are booked, not quoted, and most faults are fixed in the same visit.

Start here: one head, one zone, or every zone?

Run each zone from the controller and walk it while it runs. Controllers usually have a manual setting to run one station at a time, which makes this easy. What you see narrows it down fast:

• One head sits low while its neighbours pop up fine: the problem is at that head.
• Every head on one zone is lazy or weak: the problem is the water getting to that zone.
• Every zone is weak: the problem is upstream of all of them, at the supply.

When it's one head

• Grass has grown over it. Runners from the lawn can grow across a head and hold it down. Cut them back from around the head. If the lawn is simply taller than the head can rise, a taller pop-up fixes it.
• Grit in the nozzle or filter. Spray heads usually have a small filter screen under the nozzle that catches sand and debris. A blocked nozzle or screen gives a weak or lopsided spray. On most spray heads the nozzle unscrews from the top of the riser, so you can rinse the nozzle and screen in water. Don't poke a nozzle with wire: it scratches the opening and spoils the spray pattern.
• Water leaking around the riser. If water pools around the base of the head, the spray is weak and it only rises part-way, the seal around the riser is leaking. Grit between the riser and its seal is a common cause. Rain Bird's troubleshooting guide suggests stepping lightly on the riser while it runs, to flush the grit out. If that doesn't work, the head needs replacing.
• It's broken. A snapped riser, or a head hit by the mower or a car, shoots water up or floods, and the rest of the zone loses pressure. That head needs replacing. If it keeps happening on a verge or a driveway edge, see our tips to stop pop-ups breaking.

When a head won't go back down

A pop-up that stays up after the zone has finished usually has grit jammed between the riser and its seal, a damaged riser or seal, or a weak or broken return spring. Flushing can clear grit. For a damaged riser, seal or spring, the fix manufacturers give is a new head.

A related one: water seeping from the lowest head on a zone after watering. Some draining from the lowest head is normal for a while, as the pipe empties downhill. Leave that zone off for a couple of days. If the spot dries out, it was just the pipe draining. If it stays wet or keeps dripping, the zone's valve isn't closing fully, which is a repair job.

When a whole zone is weak

If every head on one zone struggles to pop up, look at what feeds it:

• A leak on the zone. A broken pipe, a snapped head or a cracked fitting lets water out before it reaches the other heads. Look for a boggy patch, a sunken spot, or water running from one place.
• The valve isn't fully open. Most zone valves have a flow control that can be screwed down. Turned down too far, it starves the zone. Adjusting it is a technician's job.
• Too many sprinklers for the water available. A zone is designed around the pressure and flow your supply can give. Add heads over the years, for example when a new garden bed goes in, and the zone can end up with more sprinklers than the water can run. The manufacturers' fix is splitting the zone in two.

When every zone is weak

• The retic shut-off valve is partly closed. Retic systems normally have a shut-off valve where they come off the main supply. If it was turned off for winter or for a repair, make sure it's back fully open.
• The house is using water at the same time. A washing machine or showers running while the retic waters take pressure from it. If the retic only runs weak at certain times, check what else is running then.
• A leak or blockage on the main line between the shut-off valve and the zone valves.
• Low pressure at the supply. Some properties simply have less pressure than their system was designed for. That's a design question rather than a repair: fewer sprinklers per zone, or heads and nozzles that suit lower pressure. Our guide to choosing the right sprinkler head covers which heads need how much pressure.

Too much pressure is a problem too

If your sprays look like mist or fog rather than droplets, the pressure is too high, and misting wastes water. The fix is turning the pressure down at the valve, fitting a pressure regulator, or using spray heads with a regulator built in. Rain Bird's pressure-regulated spray bodies, for example, hold the nozzle at about 30 psi (2.1 bar).

What's safe to do yourself

Safe to do: clearing grass from around heads, rinsing a nozzle and its filter, running each zone to see what's happening, and checking the shut-off valve is fully open.

Best left to a technician: adjusting the zone valves, digging for leaks, cutting into the pipe to replace heads and fittings, and anything to do with the controller's wiring.

What we do on a repair visit

We run every zone, work out where the pressure is going, and fix the cause: the leak, the valve, the blocked or broken heads. When a head needs replacing we fit a matching one, so the zone keeps watering evenly. If a zone simply has more sprinklers than your supply can run, we'll explain what splitting it would involve before any extra work goes ahead.

Repairs are booked, not quoted: a $160 minimum charge (the call-out), then labour at $40 per 15 minutes on site, plus any parts. The full breakdown is in our reticulation cost guide.

Sources: spray-head and valve faults from Rain Bird's Irrigation Troubleshooting Guide and valve troubleshooting guide, Toro's sprinkler troubleshooting guide, and the University of Florida IFAS Extension, Sprinkler tune-up!. Regulated pressure from Rain Bird's 1800 Series PRS spray heads.