The pump in my water tank outside my house is humming. what is wrong?

I came home from work to hear this humming noise. I found that it was the water tank outside my house. The pump in the bottom of the big tank is humming. I tried to unplug everything and it still hums when everything is unplugged. Any ideas why its humming or how to stop it.

"Humming" sounds come from a vibration of some kind. Water pumps some times vibrate when they're running without any water passing through. If it's a sump pump, the float that turns it on and off could be stuck in the up position. If the tank belongs to someone else, I'd call them.

If it's your pump, as a test, shut down the main power switch to your house to see if it stops. If it does, locate the circuit breaker to the pump and turn it off until you can locate the source of the problem.