Shower Pump Won't Switch Off — Keeps Running After Shower
Check the steps below first — if you're not confident, get it fixed safely today.
Post a job — we'll find you an engineer →Continuous running will burn out the pump motor. Switch off at the fused spur if you cannot resolve this quickly.
A shower pump that won't switch off is a surprisingly common problem, particularly in homes with gravity-fed systems or where mains pressure is weak. It's one of those faults that can catch people off guard — you finish your shower, turn off the valve, and the pump keeps running away merrily in the airing cupboard. The good news is that it's usually caused by one of a few straightforward issues: a stuck flow switch, a dripping shower valve, or a jammed non-return valve. The bad news is that if left running continuously, the motor will burn out within hours, which is expensive to replace. This guide walks through the most likely culprits and how to diagnose them safely. If you've tried the checks below and the pump still won't stop, it's time to switch off at the fused spur and ring a qualified plumber — there's no shame in that, and it beats a ruined motor.
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Most likely cause & what to check
Shower pumps are triggered by a flow or pressure switch. If the pump won't stop, the switch is stuck in the on position, or there is still a trickle of water flowing through.
Check the shower valve is fully closed — even a slight drip can hold a sensitive flow switch open. Turn off the shower head isolation valve temporarily to test if the pump stops.
Inspect for a stuck flow switch — this is a small paddle or diaphragm inside the pump body. If it is corroded or stuck in the open position the pump will run continuously. This usually means the pump needs servicing or replacing.
Check for a stuck non-return valve: if a non-return valve on the pump outlet is jammed open, backflow from the hot cylinder can create a continuous loop of flow through the pump.
If the pump has a manual override switch left in the on position, return it to auto.
If the problem persists, switch off at the fused spur and call a plumber — even a few hours of continuous running will destroy the motor.
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Frequently asked questions
Why does a shower pump run continuously after I turn off the shower?
The pump is controlled by a flow or pressure switch that detects when water is moving through it. If the shower valve isn't fully closed, even a tiny drip will fool the switch into thinking the shower is still running. Alternatively, the switch itself may be stuck or corroded, or a non-return valve may be allowing water to backflow and create a continuous loop.
Can I just leave the shower pump running, or will it damage it?
No — continuous running will destroy the motor within a few hours. Pump motors are designed to run intermittently and cool down between uses. Constant operation causes overheating and burnout, so you'll need an expensive replacement. Always switch off at the fused spur if the pump won't stop.
How do I test if my shower valve is the problem?
Turn off the isolation valve on the shower head itself (usually located under the bath or in the airing cupboard), then see if the pump stops. If it does, the fault is with the main shower valve not closing properly — either the cartridge needs servicing or the valve needs replacing. If the pump keeps running, the problem lies with the pump itself.
What's a flow switch, and how do I know if mine is stuck?
A flow switch is a small mechanism inside the pump (usually a paddle or diaphragm) that detects water movement and triggers the motor. If it becomes corroded by scale or debris, it can stick in the open position and won't tell the pump to stop. You'll hear the pump running even with no water flowing, and it typically means the pump needs professional servicing or replacement.
Is it safe to try to repair a shower pump myself?
Basic checks — like testing the shower valve and looking for obvious blockages — are fine. However, dismantling the pump or servicing internal components like the flow switch should be left to a plumber, as you risk damaging seals or electrical components. If you're not confident, it's better to call in a professional early.
How much does it cost to replace a shower pump?
A new pump unit typically costs between £150 and £400 depending on the model and flow rate, plus labour charges from a plumber (usually £100–£200 for fitting). It's worth getting quotes from a couple of plumbers' merchants and a local engineer. In some cases, servicing a stuck switch is cheaper than full replacement if the rest of the pump is in good condition.