Why is one sprinkler zone not working? How to diagnose a dead zone.

Every zone runs but one. That one comes up on the schedule and nothing happens — no water, no hiss, dry heads. It's one of the most common calls we get, and the good news is the fault is almost always in the same short list of places. Here's how to find it.

Is it one zone, or the whole system?

First, confirm it's really just one zone. If nothing runs at all, that's a controller, power, or water-supply problem, not a zone fault. If every zone works except one, the problem is specific to that zone's valve or the wire running to it — that's the case this guide walks through.

Step 1 — test the zone at the controller

Manually start the dead zone from the controller. On a Hydrawise system, watch for a wiring alert — it monitors the current to each valve and will often tell you the circuit's open. On any controller, if the manual start does nothing at the valve, you've narrowed it to the wire or the valve itself.

A Hydrawise controller's built-in current monitoring is a real advantage here: it measures the electrical draw on each zone and flags an open circuit or a shorted solenoid, so it often points you straight at the problem before you've lifted a valve-box lid.

Step 2 — go to the valve and listen

At the valve box for that zone, start the zone and listen for a soft click or buzz — that's the solenoid energizing. Click and buzz but no water usually means a stuck diaphragm or debris. No sound at all points to a dead solenoid or a broken wire.

Step 3 — the usual culprits

In rough order of how often we find them:

• Failed solenoid — the electrical coil that opens the valve burns out. Common, and a clean fix.
• Broken or nicked wire — a wire cut by later digging, or a corroded connection in the valve box. Wire-nut corrosion in a flooded box is a classic.
• Stuck or torn diaphragm — grit holds the valve shut (or open). More likely on older valves.
• Controller station fault — rare, but a dead output terminal will kill one zone; the controller test in Step 1 catches it.

What it's usually NOT — the heads

If a whole zone is dead, the heads are almost never the cause. No water is reaching them at all, so swapping heads won't help. Head problems look different — a head that sprays sideways, won't pop up, or mists. If that's what you're seeing, it's a head issue, not a dead zone.

(For that case, see sprinkler head not spraying. If instead water is pooling when the system's off, that's a valve leak — see water pooling around a sprinkler head.)

When to call a pro — and what a valve fix costs

If it's a solenoid or a wire, it's often a quick repair. If the valve itself needs replacing, we rebuild the whole manifold in that box, not a single valve — it's more reliable and it prevents the next failure. Pricing is by manifold size plus the valves, quoted before any work.

When a valve in a box has failed, PJL replaces the full manifold and every valve in that box together: a $135 (1–3 valve) or $285 (4–6 valve) manifold rebuild, plus $74.95 per Hunter PGV valve, plus the $95 service call. Everything's quoted up front.