Pump troubleshooting
Air in your water lines (spitting taps and air locks)
Taps that cough, splutter and spit air are telling you there’s air trapped in the water lines. It’s usually harmless and clears easily, but if it keeps coming back, the pump is drawing air in from somewhere, and that’s worth fixing.
Where the air comes from
- After any work on the plumbing or the pump, air gets in whenever the system is opened.
- After the tank or supply ran dry and drew air in.
- A pump that has lost prime.
- An air leak on the suction side of the pump, letting air in as it runs.
- A hot water system that has been drained.
Clearing trapped air (an air lock)
- Start with the tap nearest the water source or pump, and work outward.
- Open each tap fully and let it run until the spitting stops and the flow is steady, this pushes the air through.
- Do the hot and cold at each outlet.
- Flush a toilet or two to clear those lines. Once the air is out, taps should run smooth again.
If it keeps coming back
A one-off after work or a dry run clears and stays clear. If taps keep spitting air, the pump is drawing air in continuously, which means an air leak on the suction side (a loose fitting or a perished seal) or a foot valve letting the line drain and refill with air. Tighten the suction fittings and check the foot valve (see our check-valve and priming guides).
Common questions
Is air in the water dangerous?
No, it’s harmless to drink and just makes the taps splutter. It’s a nuisance, not a health issue. Persistent air, though, points to a pump drawing air in, which is worth sorting.
Why does only the hot side spit air?
That usually points at the hot water system, air can collect in the top of the tank, especially after it has been drained or refilled. Running the hot taps clears it; if it persists, have the system checked.