Humming/droning Noise While Faucets On?

[wickedred52]

When I turn on my hot or cold water, in either the bathroom or pantry, there is a humming or moaning noise that is audible. As soon as either faucet is shut off, the noise stops. I live in a two family apartment and I do not own the property. What could this possibly be, and could it be dangerous? This has been going on for about 3 weeks now.