What does a humming pool pump motor mean and how do I fix it?

A humming pool pump motor that won’t spin up almost always means a bad start capacitor. The capacitor gives the motor an initial jolt to start turning; when it fails, the motor hums, draws high current, and risks burning out. Fix it by flipping the breaker, discharging the capacitor with an insulated screwdriver, then swapping the $10–$20 cylindrical cap (match the microfarad and voltage from the label). Don’t call a pool guy yet — this is a $15 part and ten minutes of work.