A humming pool pump that won't spin is usually dead.

Yes, there are clear signs. If you hear a loud hum but the motor doesn’t turn, the start capacitor or the motor itself is shot. That’s the most common failure mode — it’s trying, but it can’t get going.

Other dead giveaways: The pump trips the breaker immediately when you turn it on. Or you see water leaking from the motor housing (seal failure, and that’s usually the end). Strange noises like grinding, screeching, or a high-pitched whine mean bearings are done for. A pump that runs hot enough to burn your hand after five minutes is also telling you to start shopping.

Sometimes a failing motor will just slow down — less flow, struggling to prime, cycling on and off. That’s the motor’s way of saying it’s tired but not dead yet. If you catch it early, you might just replace the capacitor or the seal. But if it’s humming and locked up, it’s cheaper to buy a new motor than fiddle with it.

Don’t ignore it. A seized motor can damage the impeller or the pump housing, turning a simple swap into a whole new pump.